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Systematic Review

Bioprospecting Microalgae: A Systematic Review of Current Trends

by
Juan S. Chiriví-Salomón
1,2,*,
Steven García-Huérfano
2 and
Ivan A. Giraldo
1
1
SymbIDLab, Symbiont Research & Development Corporation SAS, Cra. 2 Este #31-56 Of. 2, Chía 250002, Colombia
2
Escuela de Ciencias Agrícolas, Pecuarias y del Medio Ambiente, Universidad Nacional Abierta y a Distancia, Calle 14 Sur 14 23, Bogotá 111511, Colombia
*
Author to whom correspondence should be addressed.
Phycology 2024, 4(3), 508-532; https://doi.org/10.3390/phycology4030028
Submission received: 11 July 2024 / Revised: 9 August 2024 / Accepted: 8 September 2024 / Published: 15 September 2024
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Abstract

:
The growing interest in microalgae is driven by their potential in various bioindustries, such as biofuel production, bioremediation, and the generation of high-value biomolecules. This paper aims to systematically review the state of research on bioprospecting microalgae, their applications, and recognize trends. This study employs an exploratory and descriptive research approach, using bibliometric methods to analyze scientific production and identify emerging trends in bioprospecting microalgae research. The analysis reveals exponential publication growth, with multidisciplinary sources indicating a strong applied focus. Leading countries in this research field benefit from clear technology transfer policies, and the prevalent terms “production” and “biomass” underscore the industrial relevance. Key research areas include biofuels and bioremediation, with a combined emphasis that is often studied in cultivation and biomass production. Bioactive compounds derived from microalgae are a current trend for industrial, medical, and food applications. Although the potential for CO2 capture is acknowledged, direct studies are limited. This systematic review provides a comprehensive overview of current trends and identifies opportunities and challenges in microalgae research, highlighting its significance for sustainable development and industrial applications.

1. Introduction

Microalgae include a wide range of unicellular and colonial photosynthetic microorganisms from different taxonomic groups, such as Cyanobacteria or blue-green algae, Chlorophyta (green algae), Bacillariophyta (diatoms), Dinophyta (dinoflagellates), Haptophyta (coccolithophores), etc. [1,2,3,4]. These organisms are characterized by their microscopic size, typically ranging from a few microns to a few hundred microns, and their ability to perform photosynthesis using chlorophyll a and b or other photosynthetic pigments such as phycobiliprotein in the case of Cyanobacteria. The diversity of shapes and sizes of microalgae ranges from spherical cells to complex filamentous forms and multicellular colonies [5,6,7]. These characteristics confer microalgae vast potential for industrial applications and for producing several different metabolites [8].
Microalgal diversity has increasingly drawn attention to pursuing biological resources applicable to bioindustries. Therefore, microalgae have emerged as a promising source of biomolecules and biotechnology due to their high lipid content, secondary metabolite generation, and adaptability. The bioprospecting of microalgae has gained traction recently, driven by the necessity for sustainable solutions in energy, food, environmental restoration, and CO2 capture technology, among others [9,10,11,12,13]. Indeed, microalgae cultivation faces significant challenges; however, its potential has enabled these challenges to be gradually overcome. These challenges include optimizing cultivation conditions, developing efficient harvesting techniques, and mitigating environmental contaminants. Additionally, production’s economic feasibility and scalability are key aspects to consider. Nevertheless, ongoing research and technological innovation are paving the way to fully harness the potential of microalgae [14,15,16,17,18,19,20].
Specifically, microalgae have gained particular interest in some biotechnological applications. Biofuel production is one of the most wanted applications for microalgae, mainly due to the growing demand for renewable energy and the imperative to mitigate greenhouse gas emissions [21,22,23,24,25]. Bioremediation application is another technology widely studied for microalgae because of their ability to absorb, accumulate, and metabolize contaminants, which is why they have been used in wastewater [26,27,28,29]. On the other hand, their capability to produce biomolecules with pharmaceutical, cosmetic, and nutritional value has spurred biotechnology research [26,30,31,32,33]. Numerous scientific articles, reviews, and books have demonstrated this progress, particularly in the last decade [24,31,34,35,36,37]. However, trend reviews might be atomized by the diversity of applications and species. Given the above, this paper aims to systematically review trends in applied studies of microalgae, focusing on diminishing the atomization of knowledge through the concept appropriation of “bioprospecting”.

2. Materials and Methods

2.1. Exploratory and Descriptive Research

This study is framed within an exploratory and descriptive research approach, with a quantitative focus on analyzing the scientific production of microalgae cultivation and its various applications. Bibliometric methods were employed to identify trends, patterns, and emerging areas of interest in the scientific literature. This approach allows for a deeper understanding of the current state of research in the field of microalgae, as well as the identification of areas of opportunity and future challenges. Notably, the findings of this study have practical implications for the field, potentially guiding future research and development efforts. The methodology for the systematic review was slightly adapted from the guidelines of the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) framework [38].

2.2. Search Strategy

Searches were conducted across three primary databases: Scopus [39], Web of Science (WoS) [40], and Lens [41]. The search strategy employed the following central equation: “All(microalgae AND (application OR industry OR innovation) AND bioprospecting)”. Filters were applied to include only relevant studies. Results were quantified and classified by Document Type in any case. File exportation from databases was conducted on the 26 March 2024 cutoff. No time bias was considered in this study to completely comprehend trends through time.

2.3. Bibliometric Analysis

Bibliometric analysis was conducted using the Bibliometrix tool within RStudio [42]. The RStudio libraries Bibliometrix and openxls were utilized to process the data. The following commands were employed to unify and refine the information: setwd to set the working directory, convert2df to convert the data into a suitable format, and write.xlsx to export the results into an Excel file. Duplicates were excluded after unification. Analysis methods were executed using the default configuration in Bibliometrix [42]. No documents were excluded from the bibliometric analysis, but documents that did not directly treat microalgae were not considered for discussion.
  • Scientific Annual Production: Analysis was conducted using default parameters across the overview, sources, authors, documents, conceptual structure, and social structure tools. Scientific Annual Production was graphed using Document Type information. Production was also contrasted by Country and Total Global Citation information.
  • Analysis of sources: An analysis of sources was performed to understand trends and perspectives in the function of publications. Core sources by Bradford’s Law from Bibliometrix were executed to strengthen this analysis. WordCloud from Zygomatic was employed to complement this analysis graphically.
  • The frequency of words across Title and Abstract information was determined to elucidate patterns and trends of topics and methods/processes, respectively. The term “microalgae” was removed for WordCloud graphs to clearly evidence trends. Complementary thematic maps were executed to determine the degree of relevance and development of knowledge about these topics. Both Keywords Plus and Author’s Keywords were also used for thematic maps. A list of terms to remove and synonyms were loaded to refine these analyses.

2.4. Focused Analysis on Relevant Applications

Following the initial bibliometric analysis, a subsequent analysis focused on relevant applications was conducted. This analysis aimed to delve deeper into specific areas of interest related to microalgae. The applications considered included bioremediation, industrial and medical interest biomolecules, biofuels, food, and carbon fixation. These applications were incorporated into the search strategy using the Boolean operator AND with the central equation. The equations used for each application are detailed in Table 1. The same cleaning procedures were applied to this focused analysis. The thematic map was the only bibliometric analysis performed for these databases.
The results were documented and exported into Excel files for further examination and interpretation.

2.5. PRISMA Flow Diagram

The employed methodology is illustrated in Figure 1.

2.6. Data Collection and Storage

Raw files from WoS, Scopus, Lens, Bibliometrix files, and lists of terms of specific applications were stored as a Zenodo record [43]. This data collection also included a list of synonyms and terms to remove in Bibliometrix analyses.

3. Results and Discussion

3.1. General Search

From the central equation, the following documents were retrieved:
  • Scopus: 2990
  • Web of Science (WoS): 85
  • Lens: 208
After the unification and removal of duplicates, 2967 reviewed documents were obtained using Bibliometrix (Figure 2a). Scientific annual production has been rapidly increasing over the years. Scientific articles, including reviews and research articles, demonstrate exponential growth in their annual production (Figure 2b). Although bioprospecting is an ancient concept by definition, its use has been relatively recent, emerging in the 1990s and progressively growing over time [44]. The results of this search are consistent with the global appropriation of this concept, and differences among databases can be explained because of a potential concept bias that could strongly restrict this search. In this sense, this study reflects trends in microalgae bioprospecting.
A total of 838 sources were compiled from this search, of which only 50 sources (6% of total sources) are specific to phycology or direct reference to algal applications. The terms “science”/”sciences” are the most frequent in the name of total sources with 95 repeats in sum, followed by the term “biotechnology” with 89 repeats, then “microbiology”/”microbial” with 79 repeats in sum, then “research” with 63 repeats, and then both “environmental” and “food” with 55 repeats. Consequently, terms such as “engineering”, “technology”, “sustainable”, “applications”/”applied”, “chemistry”, and “energy”, among others, are still present. WordCloud shows trend applications through sources’ names (Figure 3).
A list of core sources was constructed using sources of zone 1 from core sources by Bradford’s Law of Bibliometrix (Table 2). Thirty sources were tabulated with specific information about the Platform Publisher, thematic specificity (SP), rank of core sources by Bradford’s Law (CS), H-index (H), G-index (G), M-index (M), number of total citations (TC), number of publications (NP), and the year when sources started to publish on the themes of this study (PY). Two sources were considered specific for phycology or direct reference to algal applications: Algal Research from ScienceDirect: ELSEVIER and Journal of Applied Phycology from Springer Link. Thirteen sources were constituted by journals from ScienceDirect: ELSEVIER, followed by MDPI (7) and Springer Link (6). The source with the highest H is Bioresource Technology (51), followed by Algal Research (38) and Renewable and Sustainable Energy Reviews (30). The same order is observed with M. For G, the third place is occupied by Marine Drugs. Concerning TC information, Bioresource Technology also reached the first rank with 8196 citations, followed by Renewable and Sustainable Energy Reviews with 4714 citations and Algal Research with 4420 citations. Finally, regarding NP, Bioresource Technology and Algal Research reached first place with 140 publications each, followed by Marine Drugs with 77 publications. This analysis demonstrates that phycology functions as an applied science, in which knowledge is transferred across various applications, but there is a need for further development within its primary discipline.
From the constructed database, scientific production per country was also observed (Figure 4, Table 3). India had the highest number of publications, coherently with the highest number of total citations. China and the USA follow it. These results demonstrate the authority of research teams in India, China, and the USA, likely due to robust or active research community, investment, or even technology transfer and commercialization models and policies’ presence [45]. Interestingly, Brazil occupies fourth place and is the only country in the Latin American region that ranked highly in this analysis. Brazil’s prominent position indicates that it is a key player and leader in scientific research within its region, contributing significantly to Latin American research output and influence [46]. Four European countries are in this list of the countries with the highest scientific production in this area. The presence of multiple European countries in the top ranks signifies the continent’s strong tradition of research excellence. These countries often lead in various scientific fields and foster cross-border collaboration, further enhancing their authority and impact.
Ten references from the explored database were chosen to elucidate interesting trends through citations (Table 4). This analysis reveals that older papers have seen a decline in their annual citation rate (TC per Year), undoubtedly due to their age. However, despite being less aligned with current trends, their presence in the top 10 underscores their enduring relevance in the field. Their reduced citation rate may reflect a shift towards newer research directions, but their inclusion in this list demonstrates their significant and ongoing contribution to the discipline. Taylor et al. (2007) [47] reached the highest number of global citations, followed by two publications by the same first author: Rawat et al. (2011) [48] and Rawat et al. (2013) [49]. Particularly, Sathasivam et al. (2019) [50] demonstrated to be the publication with the highest number of total citations per year and the highest number of normalized total citations, followed by Li et al. (2019) [34] and Kumari and Singh (2018) [35]. The bibliometric review uncovered a diverse and significant collection of highly cited articles addressing pertinent biotechnology and environmental engineering topics. The selected top ten articles span many areas, ranging from wastewater treatment to biofuel production and exploration of microorganisms associated with marine sponges. These topics reflect a growing interest in sustainable solutions to environmental challenges and the biotechnological potential of microscopic organisms. In recent years, there has been a noticeable surge in research regarding the use of microalgae for wastewater treatment and nutrient recovery [34,51]. This trend aligns with the escalating concerns over water resource scarcity and the imperative to find sustainable alternatives to conventional wastewater treatment methods.
Furthermore, integrating CO2 capture, wastewater treatment, and biofuel production through microalgae cultivation has emerged as a promising research avenue [51]. This multifunctional approach addresses climate change mitigation and the quest for renewable energy sources. Research into using lignocellulosic wastes for biofuel production has garnered attention due to its potential to reduce dependence on fossil fuels [35]. There has been particular interest in developing more efficient and cost-effective pretreatment methods and optimizing biomass conversion processes. This focus reflects a heightened awareness of the importance of utilizing renewable and sustainable resources in energy production.
Additionally, investigation into microorganisms associated with marine sponges has unveiled vast biotechnological potential in producing bioactive metabolites [47]. This emerging field offers opportunities for developing new pharmaceutical products and biofuels and studying microbial diversity in aquatic ecosystems. These themes underscore a shift towards more integrated and sustainable approaches in biotechnology and environmental engineering, emphasizing harnessing natural resources and minimizing environmental impact.
The perspectives addressed in the provided references shed light on various research areas on utilizing microalgae and other biological resources for wastewater treatment, biofuel production, and obtaining value-added products. There is an emphasis on seeking sustainable alternatives to address the water crisis and reduce dependence on fossil fuels. For example, Li et al. review the use of microalgae in wastewater treatment, highlighting the need for further research to optimize treatment processes [34]. Razzak et al. discuss CO2 capture, wastewater treatment, and biofuel production through microalgae cultivation [51]. Kumari and Singh review pretreatment methods of lignocellulosic waste for biofuel production, emphasizing the importance of combined pretreatments [35]. Sathasivam et al. and Martins et al. describe bioactive compounds produced by microalgae and their relevance in the food and pharmaceutical industries [50,54]. Günerken et al. analyze cell disruption technologies for valuable chemical production from microalgae [53]. Georgianna and Mayfield discuss the potential of algae biofuels and the need for strain and process development [52]. Rawat et al. critically evaluate biodiesel production from microalgae, from laboratory trials to large-scale production [49], and propose the dual use of microalgae for wastewater phytoremediation and biomass production for sustainable biofuels [49]. Taylor et al. explore the diversity of microorganisms associated with marine sponges and their biotechnological potential [47]. These studies suggest a broad field of study and future development in environmental biotechnology and biofuel production from renewable sources.
The most frequent words across the Title and Abstract information were “production”, “biomass”, “lipid”, “acids”, “potential”, “microorganisms”, “growth”, and “strain”. Nevertheless, some differences were found regarding terms that appear in Title information and not in Abstract information, and vice versa. For Title information, words related to microalgae species, such as “chlorella spp”, “green”, “diatom”, and “cyanobacteria”; words associated with bioprospecting methods, such as “bioprospecting”, “bioactive”, “characterization”, “extraction”, “removal”, “application”, “waste”, and “biotechnological”; and words that refer review studies, such as “future”, “perspective”, and “challenges”, were frequent and visualized in Figure 5a. The co-occurrence network defined “production” as the most frequent word after microalgae (Figure 6). For Abstract information, words related to applications, such as “process”, “energy”, “research”, “fuels”, “protein”, and “technology”; and words that mean method studies, such as “process”, “methods”, “conditions”, “results”, “system”, and “analysis”, were frequent and visualized in Figure 5b.
The database’s thematic maps were constructed using the general equation elucidated between 2 and 4 clusters based on Keywords Plus, Author’s Keywords, Title, and Abstract information (Figure 7).
Keywords Plus information generated three clusters, which are detailed in Table 5 and as follows:
  • Microalgae, with a Cluster Frequency of 10.792, comprises simple/combined terms of specific microalgal biomass production studies for industrial applications such as biofuel, biodiesel, and bioremediation;
  • Nonhuman, with a Cluster Frequency of 5.994, comprises simple/combined terms of biological composition studies for biotechnological applications such as metabolic and genetic engineering, biochemistry, and synthetic biology. Other terms associated with ecological relationships or consortia applications are included in this cluster;
  • Human, with a Cluster Frequency of 2.996, comprises simple/combined terms of biological activity studies for biomedical or veterinary applications such as bioprospecting, antimicrobial and antioxidant activity, and drugs.
The Keywords Plus clusters, focusing on specific studies and applications, suggest a well-defined interest in practical, outcome-oriented research fields. This analysis includes industrial uses such as biofuel production and bioremediation, indicating a solid drive towards sustainability and environmental management. The higher Cluster Frequency in Keywords Plus for terms related to microalgal biomass production further emphasizes this practical application focus. Terms in cluster Microalgae comprise themes that are currently considered publication trends. On the other hand, terms in cluster Nonhuman represent growing themes for research and are considered near-future trends for publication because of their high relevance and low development. Finally, terms in cluster Human are associated with emerging or declining publication themes. Considering that these keywords are extracted from the phrases frequently appearing in the titles of the cited references within the articles, terms in cluster Nonhuman are relevant to include in near-future publications to reach academic positioning.
For the Author’s Keywords, four clusters were generated by Bibliometrix, which are detailed in Table 6 and as follows:
  • Microalgae, with a Cluster Frequency of 2.509, comprises simple/combined terms of biotechnological applications of microalgae, such as bioenergy and bioremediation;
  • Lipid, with a Cluster Frequency of 2.509, comprises simple/combined terms of bioprospecting studies such as bioactive compounds, metabolic engineering, and synthetic biology;
  • Microorganisms and Seaweed have similar Cluster Frequencies of 134 and 130, respectively. These clusters comprise a few terms with low impact in this study.
The Author’s Keywords clusters, which also highlight biotechnological applications and bioprospecting studies, suggest that researchers are particularly interested in microalgae’s biochemical and genetic potential. Clusters related to lipids and other microorganisms imply a comparative approach, where microalgae are studied alongside other biological entities to uncover unique or superior traits. Terms in clusters Microalgae and Lipid represent growing themes for researchers and are considered trends of interest for research groups because of their high relevance and low development. Finally, terms in clusters of Microorganisms and Seaweed are associated with niche themes, implying that researchers frequently used them for their publications but that they have lost relevance over time. Trend terms in this analysis are congruent with Keywords Plus information, which elucidates coherence between trend publications among sources and authors.
Title information generated three clusters, which are described in Table 7 and are as follows:
  • Potential, with a Cluster Frequency of 6.381, comprises simple terms of potential and bioprospecting application of microalgae;
  • Microalgae, with a Cluster Frequency of 5.997, comprises simple terms of interested studies of perspective and trends and industrial processing application of microalgae and their production;
  • Lipid, with a Cluster Frequency of 1.930, comprises simple terms of culture and growth systems for several purposes.
Title information clusters reveal trends and industrial applications, suggesting that the titles of the research papers often emphasize the broader impact and potential future directions of the studies. This fact can indicate a strategic approach to framing research regarding its relevance to current scientific and industrial challenges. Terms in the Potential cluster comprise themes currently considered research trends. Terms in the Microalgae cluster represent growing themes of interest for researchers and are considered near-future trends among research groups because of their high relevance and low development. Finally, terms with emerging or declining trends are grouped in the Lipid cluster. Terms in clusters Potential and Microalgae must be considered in present and near future research projects.
Finally, the Abstract information generated two clusters, which are detailed in Table 8 and are as follows:
  • Production, with a Cluster Frequency of 56.387, comprises simple or combined terms associated with methods and processes of the microorganisms’ bioproducts, with a broader focus on various applications and research areas.
  • Microalgae, with a Cluster Frequency of 27.138, comprises simple or combined terms around the study of microalgae and their potential uses, particularly in producing biodiesel and other biofuels.
The abstract information, with its dominant clusters related to biotechnological applications and specific methodological approaches, shows a detailed methodological focus. Abstracts will likely delve into the techniques and procedures used in microalgae research, aligning with the high Cluster Frequency for terms related to sampling and extraction methods. This methodological emphasis in abstracts suggests that researchers prioritize sharing detailed processes and innovations in their methodologies, potentially to facilitate replication and further development by others in the field.
These different emphases reflect a comprehensive research approach, addressing the practical applications and the underlying scientific principles, thereby fostering a robust understanding and utilization of microalgae across various domains.
Focusing on practical applications, academic staff and researchers can directly contribute to biofuel production, environmental remediation, and industrial bioprocessing, driving immediate advancements in sustainable technologies. The emphasis on specific study areas ensures that applied research is grounded in solid empirical data, making the solutions viable and scalable. Concurrently, exploring biochemical and genetic aspects through the Author’s Keywords indicates a deeper dive into the fundamental science of microalgae. This approach advances the basic understanding of these microorganisms and uncovers new possibilities for their use in synthetic biology, metabolic engineering, and the production of high-value bioproducts. By identifying and manipulating the genetic and metabolic pathways, researchers can enhance the efficiency and yield of desired compounds, leading to more effective and innovative applications [50,57]. Titles often highlight broader trends and potential impacts, suggesting a strategic vision that frames individual studies within the larger context of scientific and industrial advancements. This aspect helps attract attention and funding and aligns research efforts with global priorities, such as sustainability and green technology [58,59,60]. It reflects a forward-thinking perspective considering microalgae research’s long-term implications and scalability. Abstracts, on the other hand, typically emphasize detailed methodologies and technical processes. This information focuses on how research ensures the scientific community can replicate, validate, and build upon existing work [61]. By providing clear and precise descriptions of sampling, extraction, and processing techniques, researchers contribute to a cumulative consolidation of knowledge that enhances the reliability and efficiency of microalgae utilization. Integrating these emphases—practical applications, fundamental science, strategic impact, and methodological rigor—creates a well-rounded research field. This comprehensive approach accelerates technological innovation and deepens our scientific understanding, leading to more robust and versatile applications of microalgae across various domains. The interplay between applied research and foundational science thus ensures that advancements are grounded in solid theory and directed toward practical, real-world benefits.

3.2. Specific Applications

To better understand specific application trends, bibliometric analyses were performed on biofuel technology, biomolecule production, bioremediation, CO2 fixation, and food technology. Table 9 details the number of documents retrieved from these analyses.
Thematic maps of Title information allow for the comprehension of trends among specific applications. They consider clusters of terms and group themes that can be positioned by relevance and development degree (Figure 8). Particular focus was placed on the Basic Themes area, considering clusters represent transversal themes and opportunities to develop relevant knowledge [62].

3.2.1. Bioremediation: Biomass Production for Multipurpose Technologies Trend

Bioremediation’s map displays four clusters, with the Microalgae and Lipid clusters being particularly interesting due to their relevance. The Microalgae cluster demonstrated the highest Cluster Frequency with 4.585 and comprises terms related to production and biomass, wastewater treatment, combined strategies with biofuels and energy technology, derived value-added products, processes, and sector application. On the other hand, the Lipid cluster, with a Cluster Frequency of 2.702, comprises terms associated with the production of lipid and fatty acids, cultivation and growth conditions, biochemical and metabolic studies, and optimizations and enhancement processes. Other clusters in this analysis show transversal interests that can be used to position future studies, but their terms should not be declared as protagonists (Table 10).
Given that the thematic map was generated from document titles related to bioremediation, this cluster offers insights into the prevailing research themes and emerging trends in this field. Research focuses on microalgae species used for bioremediation or, specifically, phycoremediation. Several titles comprise terms such as production, biomass, wastewater, and treatment, indicating a strong focus on biomass generation from these microorganisms for various applications, including bioremediation and a practical application of this biomass in treating industrial and municipal wastewater. Interestingly, concepts such as biofuel, biodiesel, bioethanol, energy, and bioenergy were also frequent, indicating an interest in combined technologies. Terms associated with environmental and economic benefits also constituted this cluster, suggesting an association between this biotechnology and its declaration across different application sectors. There is a strong emphasis on developing efficient processes and technologies, evaluating their economic viability, and exploring their applications across various industrial and environmental sectors. This multifaceted approach points out the potential of bioremediation not only as a solution for pollution but also as a contributor to sustainable energy and resource management [63,64,65,66,67,68,69,70].

3.2.2. Industrial and Medical Interest Biomolecules: Bioproduct Synthesis and Their Sustainable Production Trend

Analysis of Industrial and Medical Interest Biomolecules generated three clusters, of which Microalgae and Production clusters are of interest in this trend analysis. No clusters were in the Basic Themes area, but the Microalgae cluster is between it and Motor Themes. This position suggests a recent growing trend of developing knowledge in its terms. The Microalgae cluster comprises terms related to biological sources of bioproduct generation, lipids and fatty acid production, antioxidant and antimicrobial compounds, and several applications such as nutraceuticals, therapeutic applications, nanotechnology, industrial and aquaculture. On the other hand, the Production cluster, which is between Motor and Niche Themes, presents terms with high relevance and a high degree of development, and they are constantly of interest. These terms comprise production and sustainability relationship concepts, commercial focus, challenges and perspectives, and integral impacts. Finally, the Marine cluster shows cross-interests that can be used to position future studies, but their terms should be considered as something other than the main themes (Table 11).
There is an opportunity to develop innovations in biomedical and industrial applications of value-added products from microalgae because of their positioned clusters between thematic map areas. Specifically, bioprospecting microalgae for bioproduct synthesis and their sustainable production would be highly interesting in the present and near future [53,71,72,73,74,75,76,77,78]. Bioprospecting microalgae for pharmaceuticals and secondary metabolites is highly promising due to its ability to produce diverse bioactive compounds such as antioxidants, antimicrobials, and anti-inflammatories [79,80]. Microalgae like Chlorella, Arthrospira, Dunaliella, and Haematococcus offer valuable compounds like carotenoids, phycocyanin, dinotoxins, and novel metabolites [80]. Their rapid growth and adaptability make sustainable, large-scale production feasible. Advanced biotechnological tools can enhance yield and efficiency, making microalgae a key resource for developing new, eco-friendly medical treatments and health products. Microalgae hold significant industrial and medical potential, offering sustainable solutions for biomaterials, biodegradable plastics, and nutraceuticals due to their high lipid content and rich nutrient profile. They provide essential fatty acids, vitamins, and proteins for agricultural applications, dietary supplements, and functional foods, and their bioactive compounds are being researched for cancer therapy, cardiovascular health, and neuroprotection [36,81,82,83]. Nevertheless, although microalgae bioproducts have strong potential, their commercialization still needs improvement due to research funding challenges, small-scale operations, and policy implementation [84,85].

3.2.3. Biofuels: Microalgae Biorefinery for Combined Actions Trend

Interestingly, the Biofuels map shows similar patterns in its clusters with the Bioremediation map, which is congruent with suggestions made in the Bioremediation analysis for combined technologies. The Microalgae cluster in the Biofuels map (Cluster Frequency = 4.763) presents terms showing various biofuel types, including biodiesel and bioethanol. This cluster also comprises terms associated with technological and methodological advances in production, biomass, fermentation, co-product generation, and dual action with wastewater treatments. Conversely, the Lipid cluster highlights comprehensive and multidisciplinary terms for optimizing microalgae cultivation and biofuel production. The focus on lipid and fatty acid production, strain improvement, nutrient management, and environmental optimization indicates a robust effort to enhance the efficiency and yield of biofuels as a continuous field of knowledge development. Finally, the Microorganisms and Potential clusters add terms that could be strengths in future biofuel studies (Table 12).
The research trends in biofuels from microalgae indicate a comprehensive and multidisciplinary approach [24,86,87,88,89,90,91]. Microalgae’s central role, combined with a strong focus on sustainable production, wastewater treatment, and the biorefinery concept, highlights the potential of this area to contribute significantly to green energy solutions [37]. The focus around the turn of the century shifted to studies on the unsustainability of petroleum fuels and the exploration of alternative sources due to the limited capacity of biodiesel from oil crops, which introduced microalgae as a uniquely capable option [92,93]. This notable trend evolved to study microalgae’s high photosynthetic efficiency and oil yield, noting the technical challenges and opportunities in biomass production, which are critical for commercial viability [94]. Technological advancements, economic viability, and co-product valorization drive the research forward. This dynamic field is poised to address critical environmental challenges while providing renewable energy and valuable byproducts. Now, the trend in biofuel production derived from microalgae is focused on combined actions with other biotechnology, but also in studying microalgae in biorefinery, which means that current trends are focused on metabolic processes that reach efficiencies for engineering.

3.2.4. Food: Functional Food and Bioactive Compounds Trend

For the Food search, the thematic map shows the formation of four clusters, from which clusters of Microalgae (Cluster Frequency = 4.972) and Production (Cluster Frequency = 3.949) are given special attention for the current analysis. The Microalgae cluster presents several terms associated with the source (microalgal species and place), showing the diversity and bioactivity of microalgae for this purpose. On the other hand, the Production cluster group terms are associated with sustainability and previous analyses of a cluster named Production. Coincidently, the terms Biofuels and Bioremediation are observed in this cluster, which suggests a combined action, as was observed in the Biofuels and Bioremediation analyses. The terms in the Lipid and Growth clusters also show concepts that can be used to strengthen trend studies on food technology and microalgae (Table 13).
The dominant cluster in food technology research with microalgae highlights a comprehensive exploration of their potential applications, particularly in health, nutrition, and industrial uses. The focus on bioactive compounds, biotechnological advancements, and sustainable production methods reflects a growing trend toward integrating microalgae into the food industry. This cluster emphasizes the importance of continued research and development to fully realize the commercial and health benefits of microalgae, positioning them as a valuable resource for the future of food technology [76,80,95,96,97,98]. The trends emphasize the role of microalgae in producing sustainable biofuels, treating wastewater, and contributing to a circular economy through biorefineries. Ongoing research addresses challenges and explores new opportunities to harness the full potential of microalgae, positioning them as a vital resource for sustainable food technology and environmental management.

3.2.5. Carbon Fixation: Emerging Opportunity to Promote Sustainability Trend

The last analysis based on the Carbon Fixation theme demonstrated a more exciting pattern compared to previous analyses due to the formation of only two clusters, with a clear dominance of the Microalgae cluster (Cluster Frequency = 4.589), which is in the Basic Themes area. This cluster comprises terms associated with production, multidisciplinary applications, and prospective concepts. By its side, the Wastewater cluster (Cluster Frequency = 2.660) includes terms related to biomass, cultivation, and strain characterization (Table 14). Interestingly, no direct concepts or low relationship of carbon fixation were found in both clusters, suggesting an absence of title declarations about this theme. This finding provides an opportunity to research microalgae and its focused application in carbon fixation [99,100,101,102]. There is a strong need to develop this microalgal research field due to its incredible relevance and low degree of development.
The biotechnological applications of microalgae have captured significant attention in scientific research, highlighting their potential in different fields, from biofuel production to environmental bioremediation. Different reviews have underscored the multifaceted uses of microalgae, focusing on their role as a raw material for high-value products, carbon sequestration, and wastewater treatment [31,37]. Critical reviews also further emphasize the importance of microalgae in sustainable energy solutions and the production of bioactive compounds [71,101]. Despite these advancements, a core trend in this study is the increasing focus on bioprospecting as a fundamental element in unlocking the full potential of microalgae biotechnology. This trend reflects the growing recognition that exploring and harnessing the diversity of bioactive molecules within microalgae is essential for advancing medical, industrial, and environmental applications. Thus, bioprospecting has become a cornerstone of current research, paving the way for discoveries and innovations in applied phycology.
Although microalgae are currently studied in terms of biomass production for several purposes, such as bioremediation and biofuel generation, microalgae biotechnology is still a promising multidisciplinary research field. Research in bioactive molecules for medical or industrial applications and carbon fixation or sequestration constitutes a call for researchers and R&D centers. Challenges, prospects, and opportunities are trending in several current review studies, meaning that applied phycology is growing.

4. Conclusions

The publication of research concerning microalgae exhibits an exponential growth trend, underscoring the burgeoning interest and research activities in this domain. The multidisciplinary nature of the publishing sources reveals a primarily applied focus in the studies of these microorganisms. Among the core sources identified, a minority specialize in phycology, while the rest span various fields, highlighting the wide-ranging applications and interest in microalgae research.
Countries leading in microalgae research often have well-defined technology transfer models and policies. This correlation suggests that clear technological frameworks and support mechanisms significantly contribute to advancements and leadership in this field.
The literature on microalgae research is dominated by terms such as “production” and “biomass”, indicating a strong industrial focus. This emphasis on practical applications reflects the efforts to optimize the use of microalgae in various industries. The significant research in bioremediation and biofuels further highlights the practical relevance of microalgae. These areas are frequently studied together, accompanied by research into microalgae cultivation and biomass production. Additionally, there is notable interest in leveraging microalgae to generate high-value bioproducts and as a source of nutrition, highlighting the wide-ranging practical applications of microalgae and the relevance of any research.
While there are relatively few direct studies demonstrate the potential of microalgae for CO2 capture, the photosynthetic nature of these microorganisms provides a compelling justification for ongoing research in this area. This potential for CO2 capture not only features the environmental benefits of microalgae but also inspires future research direction, highlighting the exciting possibilities for microalgae to contribute to environmental sustainability.
The expansive and multidisciplinary research on microalgae reflects their versatile applications and significant industrial relevance. The leading countries in this research field benefit from robust technology transfer policies, and the focus on production and biomass draws attention to the practical and industrial motivations driving this research. While CO2 capture remains underexplored, it represents a promising avenue for future studies, aligning with global sustainability goals.
To further enhance the impact of microalgae research, it is critical to recognize the growing importance of bioprospecting in this field. Exploring and identifying bioactive molecules within microalgae are increasingly recognized as key to unlocking new applications in medicine, industry, and environmental management. As the research community continues to delve into the diverse potential of microalgae, bioprospecting emerges as a fundamental approach that expands the scope of applied phycology and aligns with the global pursuit of innovative and sustainable biotechnological solutions. By integrating bioprospecting with existing research avenues, such as biomass production and bioremediation, the field of microalgae biotechnology is poised to make significant strides in addressing some of the most pressing challenges of our time. This holistic approach underscores the need for continued interdisciplinary collaboration and investment in research and development, ensuring that the full potential of microalgae is realized across various sectors.

Author Contributions

Conceptualization, J.S.C.-S. and I.A.G.; methodology, J.S.C.-S.; software, J.S.C.-S. and S.G.-H.; validation, J.S.C.-S. and S.G.-H.; formal analysis, J.S.C.-S.; investigation, J.S.C.-S.; resources, J.S.C.-S. and I.A.G.; data curation, J.S.C.-S. and S.G.-H.; writing—original draft preparation, J.S.C.-S.; writing—review and editing, J.S.C.-S. and S.G.-H.; visualization, J.S.C.-S.; supervision, J.S.C.-S. and I.A.G.; project administration, I.A.G.; funding acquisition, I.A.G. All authors have read and agreed to the published version of the manuscript.

Funding

This research was funded by Ministerio de Ciencia, Tecnología e Innovación-Minciencias of Colombia through the project “Sistema de biosorción de CO2 para la generación de Biomasa Multipropósito-SiBioCO2” (Code No. 92998), under the Convocatoria No. 926 de 2022 Convocatoria Senainnova para el Fomento a la Innovación y desarrollo Tecnológico “por la reactivación del País” 2022-área estratégica bioeconomía” (Resolución No. 0425 de mayo 5, 2022), through the Contingent Recovery Financing Contract No. 80740-220-2022 executed between Fiduciaria La Previsora S.A.-FIDUPREVISORA S.A., acting as representative and administrator of the National Fund for Financing for Science, Technology and Innovation, Fundación Francisco José de Caldas and Symbiont Research & Development Corporation S.A.S. Universidad Nacional Abierta y a Distancia also partially funded this publication by providing research time for the first author.

Institutional Review Board Statement

Not applicable.

Informed Consent Statement

Not applicable.

Acknowledgments

We gratefully acknowledge the technical support in Bibliometrix use and PRISMA application provided by Jhon Fredy Escobar Soto and Sebastian Robledo, respectively. We also thank Hector Gutiérrez for his help in graph editing.

Conflicts of Interest

The authors declare no conflicts of interest.

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Phycology 04 00028 g001
Figure 1. PRISMA Flow Diagram.
Figure 1. PRISMA Flow Diagram.
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Figure 2. Annual Scientific Production from central search equation: “All(microalgae AND (application OR industry OR innovation) AND bioprospecting)”: (a) Annual Scientific Production by Document Type; (b) behavior trend for Annual Scientific Production.
Figure 2. Annual Scientific Production from central search equation: “All(microalgae AND (application OR industry OR innovation) AND bioprospecting)”: (a) Annual Scientific Production by Document Type; (b) behavior trend for Annual Scientific Production.
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Figure 3. WordCloud of total source names from the central search equation database.
Figure 3. WordCloud of total source names from the central search equation database.
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Figure 4. Density map of the world’s scientific production according to the database resulting from the central search equation: “All(microalgae AND (application OR industry OR innovation) AND bioprospecting)”. The blue scale demonstrates the abundance of scientific production. The gray color demonstrates the absence of information about scientific production.
Figure 4. Density map of the world’s scientific production according to the database resulting from the central search equation: “All(microalgae AND (application OR industry OR innovation) AND bioprospecting)”. The blue scale demonstrates the abundance of scientific production. The gray color demonstrates the absence of information about scientific production.
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Figure 5. WordCloud of the main search equation: “All(microalgae AND (application OR industry OR innovation) AND bioprospecting)” and generated from: (a) Title information; (b) Abstract information.
Figure 5. WordCloud of the main search equation: “All(microalgae AND (application OR industry OR innovation) AND bioprospecting)” and generated from: (a) Title information; (b) Abstract information.
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Figure 6. Co-occurrence network for “All(microalgae AND (application OR industry OR innovation) AND bioprospecting)” and generated from Title information.
Figure 6. Co-occurrence network for “All(microalgae AND (application OR industry OR innovation) AND bioprospecting)” and generated from Title information.
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Figure 7. Thematic maps of the central search equation: “All(microalgae AND (application OR industry OR innovation) AND bioprospecting)” and generated from: (a) Keywords Plus information; (b) Author’s Keywords information; (c) Title information; (d) Abstract information.
Figure 7. Thematic maps of the central search equation: “All(microalgae AND (application OR industry OR innovation) AND bioprospecting)” and generated from: (a) Keywords Plus information; (b) Author’s Keywords information; (c) Title information; (d) Abstract information.
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Figure 8. Thematic maps of the specific applications’ equations: (a) bioremediation; (b) industrial and medical interest biomolecules; (c) biofuels; (d) food; (e) carbon fixation.
Figure 8. Thematic maps of the specific applications’ equations: (a) bioremediation; (b) industrial and medical interest biomolecules; (c) biofuels; (d) food; (e) carbon fixation.
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Table 1. Search Equations for Specific Applications.
Table 1. Search Equations for Specific Applications.
ApplicationSearch Equations
BioremediationAll(bioremediation OR “waste water” OR wastewater OR biodegradation)
Industrial and Medical Interest BiomoleculesAll(biomolecules OR drugs)
BiofuelsAll(biofuel OR biodiesel OR energy OR bioenergy)
FoodAll(food OR protein)
Carbon Fixation 1All((carbon OR CO2 OR “carbon dioxide”) AND (fixing OR fixation OR absorption OR sequestration OR capture OR assimilation OR reduction OR incorporation))
1 The equation for searching studies related to carbon fixation is extensive due to the various terms used in the scientific literature to describe this process. This wide range of terms aims to ensure the inclusion of relevant studies addressing different aspects of carbon fixation in microalgae.
Table 2. List of core sources according to Bradford’s Law.
Table 2. List of core sources according to Bradford’s Law.
SourcePlatform PublisherSPCSHGMTCNPPY
Algal ResearchScienceDirect: ELSEVIERSP.138612.92344201402012
Bioresource TechnologyScienceDirect: ELSEVIERNSP.251873.64381961402011
Marine DrugsMDPINSP.3245022563772013
Journal of Applied PhycologySpringer LinkSP.420301.6671037572013
Renewable And Sustainable Energy ReviewsScienceDirect: ELSEVIERNSP.530372.54714372013
MoleculesMDPINSP.615301.875917362017
Science of The Total EnvironmentScienceDirect: ELSEVIERNSP.717332.4291127332018
Biomass Conversion and BiorefinerySpringer LinkNSP.8792.333127322022
Frontiers in MicrobiologyFrontiersNSP.99241599262016
MicroorganismsMDPINSP.109201433252016
Bioenergy ResearchSpringer LinkNSP.1111230.917655232013
Bioresource Technology ReportsScienceDirect: ELSEVIERNSP.129131.5187232019
ChemosphereScienceDirect: ELSEVIERNSP.1312222.4637222020
Scientific ReportsNatureNSP.1410161283222015
Biotechnology AdvancesScienceDirect: ELSEVIERNSP.1515211.51650212015
Environmental Science and Pollution ResearchSpringer LinkNSP.1610201428212015
Renewable EnergyScienceDirect: ELSEVIERNSP.1713211.083834212013
Journal of Cleaner ProductionScienceDirect: ELSEVIERNSP.18142021095202018
Applied Sciences (Switzerland)MDPINSP.199161.5266192019
FuelScienceDirect: ELSEVIERNSP.209191.5440192019
Applied Biochemistry and BiotechnologySpringer LinkNSP.2111180.846499182012
Biomass And BioenergyScienceDirect: ELSEVIERNSP.2213181.083457182013
FoodsMDPINSP.238141.6211182020
Biocatalysis and Agricultural BiotechnologyScienceDirect: ELSEVIERNSP.247170.583307172013
International Journal of Hydrogen EnergyScienceDirect: ELSEVIERNSP.2511171.222320172016
Journal of Chemical Technology and BiotechnologyWileyNSP.268140.615218172012
3 BiotechSpringer LinkNSP.277140.7196162015
Critical Reviews in BiotechnologyTaylor & Francis OnlineNSP.2811160.917671162013
EnergiesMDPINSP.2910160.769505162012
International Journal of Molecular SciencesMDPINSP.308160.8433162015
“SP” is thematic specificity. “SP.” is specific to the theme of this study. “NSP.” is non-specific for the theme of this study. “CS” is the rank of core sources by Bradford’s Law. “H” is the H-index. “G” is the G-index. “M” is the M-index. “TC” is the number of total citations. “NP” is the number of publications. “PY” is the year when sources start to publish on the theme of this study.
Table 3. Top 10 countries by number of publications.
Table 3. Top 10 countries by number of publications.
CountryNPTC
India70610,363
China3199085
USA1987564
Brazil1533153
Portugal1082059
Italy891615
Malaysia752002
Canada742582
South Korea742144
France651897
“NP” is the number of publications. “TC” is the total citations.
Table 4. Top 10 documents with the most global citations.
Table 4. Top 10 documents with the most global citations.
PaperSourceTCTC per YearNorm. TC
Taylor et al., 2007 [47]Microbiology and Molecular Biology Reviews108360.172.52
Rawat et al., 2011 [48]Applied Energy87662.577.09
Rawat et al., 2013 [49]Applied Energy75062.508.86
Georgianna and Mayfield, 2012 [52]Nature58845.236.64
Günerken et al., 2015 [53]Biotechnology Advances52752.707.44
Sathasivam et al., 2019 [50]Saudi Journal of Biological Sciences49983.1714.86
Kumari and Singh, 2018 [35]Renewable and Sustainable Energy Reviews48569.2911.12
Razzak et al., 2013 [51]Renewable and Sustainable Energy Reviews47439.505.60
Li et al., 2019 [34]Bioresource Technology42170.1712.54
Martins et al., 2013 [54] 1Marine Drugs39535.917.51
“TC” is the total citations. “TC per Year” is the total citations per year. “Norm. TC” is normalized total citations. 1 In the bibliometric analysis for Most Global Cited Documents in Bibliometrix, two documents are higher in rank [55,56] than the chosen one [54] but do not directly treat microalgae topics. The database includes these references because they are connected to microalgae topics through their reference list or citations.
Table 5. Top 10 terms in generated clusters for Keywords Plus information.
Table 5. Top 10 terms in generated clusters for Keywords Plus information.
MicroalgaeNonhumanHuman
TermOccurrenceTermOccurrenceTermOccurrence
microalgae946nonhuman742human268
biomass602metabolism378animal145
biofuel427biotechnology226antioxidant126
lipid332bacteria220unclassified drug183
microorganisms536controlled study242bioproducts96
wastewater215chemistry238seaweed68
fatty acid264cyanobacteria127polysaccharide72
chlorella spp217carotenoids131biodiversity77
biodiesel269fungi97astaxanthin72
nitrogen161diatom77antioxidant activity89
Table 6. Top 10 terms in generated clusters for Author’s Keywords information.
Table 6. Top 10 terms in generated clusters for Author’s Keywords information.
MicroalgaeLipidMicroorganismsSeaweed
TermOccurrenceTermOccurrenceTermOccurrenceTermOccurrence
microalgae775lipid152microorganisms53seaweed49
biofuel260cyanobacteria107enzymes21bioactivity23
biodiesel198fatty acid106heavy metals21lipidomics22
biomass125carotenoids89phytoremediation21glycolipids18
wastewater97antioxidant81biodegradation18phospholipids18
biorefinery90bioactive compounds69metagenomics14mass spectrometry14
bioremediation79bioprospecting69nanoparticles14
wastewater treatment79diatom68toxicity14
chlorella spp73pigments54
sustainability55astaxanthin53
Table 7. Top 10 terms in generated clusters for Title information.
Table 7. Top 10 terms in generated clusters for Title information.
PotentialMicroalgaeLipid
TermOccurrenceTermOccurrenceTermOccurrence
potential281microalgae1088lipid242
microorganisms254production686growth139
marine249biomass265cultivation132
applications156wastewater247chlorella spp121
acids142biofuel218effects117
compounds129sustainable180nutrients95
source130biodiesel169removal81
fatty120treatment117enhancement69
bioprospecting122industrial108culture53
bioactive113future95optimization52
Table 8. Top 10 terms in generated clusters for Abstract information.
Table 8. Top 10 terms in generated clusters for Abstract information.
ProductionMicroalgae
TermOccurrenceTermOccurrence
production1573microalgae1679
potential1267biomass1066
microorganisms740lipid800
source976acids789
industrial868growth999
compounds721strain690
biofuel613wastewater457
environment825cell630
process764fatty566
species655biodiesel415
Table 9. Number of documents analyzed from specific applications’ equations.
Table 9. Number of documents analyzed from specific applications’ equations.
DatabaseBioremediationIndustrial and Medical Interest BiomoleculesBiofuelsFoodCarbon Fixation
Scopus18781715248726511386
Web of Science (WoS)171153368
Lens626213515070
Final Data 118871724253425431415
1 Number of documents after unification and removal of duplicates.
Table 10. Top 20 terms in the Bioremediation clusters.
Table 10. Top 20 terms in the Bioremediation clusters.
MicroalgaeLipidMicroorganismsMarine
TermOccurrenceTermOccurrenceTermOccurrenceTermOccurrence
microalgae835lipid158microorganisms165marine88
production529cultivation114sustainable148applications87
wastewater250growth109environment74application56
biomass226chlorella spp106challenges70compounds56
biofuel177nutrients90bioremediation69bacteria50
potential173removal80perspective69biotechnological46
biodiesel137acids73recent69bioactive40
treatment116effects76future59fungi37
industrial74strain72technology57biotechnology35
source75fatty64current51natural35
green70diatom56advances46extraction29
bioprospecting69enhancement50approaches43synthesis28
waste66isolated48resource39pigments27
biorefinery63characterization46prospects38diversity24
products61effluent42trends36exploring23
process48vulgaris43remediation33health22
approach48species39emerging30nanoparticles19
energy45municipal39engineering26yeast17
cyanobacteria45conditions36enzymes26functional15
system43culture36heavy26seaweed14
Table 11. Top 20 terms in the Industrial and Medical Interest Biomolecules clusters.
Table 11. Top 20 terms in the Industrial and Medical Interest Biomolecules clusters.
MicroalgaeProductionMarine
TermOccurrenceTermOccurrenceTermOccurrence
microalgae534production289marine219
lipid111microorganisms178potential180
activity98sustainable107applications127
acids87biomass104compounds118
bioprospecting90products90bioactive105
antioxidant84industrial71source89
diatom78perspective67natural86
fatty74wastewater64pigments69
growth58biofuel63food65
effects57future61biotechnological58
cell48recent57metabolites56
extraction52challenges55bacteria54
green53cultivation53plant51
application53current54fungi48
carotenoids49environment48health36
characterization49biotechnology47diversity30
strain48advances42synthetic24
cyanobacteria46biorefinery42functional23
seaweed45engineering41therapeutic23
isolated39development39discovery22
Table 12. Top 20 terms in Biofuels clusters.
Table 12. Top 20 terms in Biofuels clusters.
MicroalgaeLipidMicroorganismsPotential
TermOccurrenceTermOccurrenceTermOccurrenceTermOccurrence
microalgae1056lipid236microorganisms188potential236
production674acids136sustainable173marine163
biomass263cultivation129industrial97applications139
wastewater251growth130perspective89source105
biofuel223chlorella spp121challenges87bioprospecting101
biodiesel173fatty116future86compounds86
treatment117strain97recent79bioactive73
green87effects98products75application68
waste76nutrients96technology71extraction66
biorefinery73characterization86environment70cyanobacteria66
analysis59diatom81current65food65
cell58removal77bioremediation60biotechnological59
plant57isolated64development58natural55
approach57enhancement63advances54bacteria51
process55activity61biotechnology54pigments49
energy54antioxidant56engineering51metabolites43
system52species53approaches50synthesis39
feedstock44accumulation47fungi48diversity37
metabolic44vulgaris47prospects50biological34
stress44conditions46resource44seaweed34
Table 13. Top 20 terms in Food clusters.
Table 13. Top 20 terms in Food clusters.
MicroalgaeProductionLipidGrowth
TermOccurrenceTermOccurrenceTermOccurrenceTermOccurrence
microalgae882production561lipid179growth112
potential253biomass230acids123cultivation98
microorganisms229wastewater181fatty105chlorella spp92
marine208biofuel165activity104nutrients70
applications150sustainable159antioxidant91enhancement57
compounds119biodiesel111effects91removal55
source115perspective93diatom82enhanced44
bioactive106future89characterization81culture41
bioprospecting105challenges84strain76conditions41
products100treatment84isolated61assessment39
natural96recent82carotenoids59vulgaris39
industrial93current71evaluation48accumulation32
food83environment69species47freshwater32
pigments79biorefinery68composition46effluent27
green76waste66optimization40anaerobic27
extraction72technology62properties40nitrogen26
cyanobacteria71advances58stress40productivity25
cell65approach53chemical39native24
application68bioremediation52screening38efficient22
fungi65process50antimicrobial33light22
Table 14. Top 20 terms in Carbon Fixation clusters.
Table 14. Top 20 terms in Carbon Fixation clusters.
MicroalgaeWastewater
TermOccurrenceTermOccurrence
microalgae625wastewater165
production385biomass164
biofuel153lipid104
microorganisms117biodiesel101
potential116cultivation85
sustainable114treatment81
applications85growth68
challenges65chlorella spp62
marine64acids58
perspective62nutrients55
source59green54
industrial58fatty52
recent58removal49
biorefinery52plant40
future50effects41
products49strain39
waste45characterization36
diatom44process35
bioprospecting42system36
technology42carbon34
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Chiriví-Salomón, J.S.; García-Huérfano, S.; Giraldo, I.A. Bioprospecting Microalgae: A Systematic Review of Current Trends. Phycology 2024, 4, 508-532. https://doi.org/10.3390/phycology4030028

AMA Style

Chiriví-Salomón JS, García-Huérfano S, Giraldo IA. Bioprospecting Microalgae: A Systematic Review of Current Trends. Phycology. 2024; 4(3):508-532. https://doi.org/10.3390/phycology4030028

Chicago/Turabian Style

Chiriví-Salomón, Juan S., Steven García-Huérfano, and Ivan A. Giraldo. 2024. "Bioprospecting Microalgae: A Systematic Review of Current Trends" Phycology 4, no. 3: 508-532. https://doi.org/10.3390/phycology4030028

APA Style

Chiriví-Salomón, J. S., García-Huérfano, S., & Giraldo, I. A. (2024). Bioprospecting Microalgae: A Systematic Review of Current Trends. Phycology, 4(3), 508-532. https://doi.org/10.3390/phycology4030028

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