Yeast - Fermentation

A special issue of Fermentation (ISSN 2311-5637). This special issue belongs to the section "Microbial Metabolism, Physiology & Genetics".

Deadline for manuscript submissions: closed (15 April 2023) | Viewed by 43878

Special Issue Editor

College of Life Science and Technology, Beijing University of Chemical Technology, Beijing, China
Interests: yeast; fermentation; fermentation process; co-culture; stress tolerance; chemicals; foods; interaction between microorganisms; fermentation efficiency; metabolic engineering; strain development

Special Issue Information

Dear Colleagues,

Due to their advantages, yeast strains, especially Saccharomyces cerevisiae, have been widely used in industrial fermentation, such as the significant production of bioethanol, chemicals, and beverages. However, during the fermentation process, yeast cells have to cope with a variety of stresses such as the accumulation of ethanol, high temperature, high osmotic stress, a large amount of sugar, inoculation amount, and oxidation. To increase the fermentation efficiency, yeast strains with higher stress tolerance are highly desirable. Moreover, fermentation performed by S. cerevisiae and other yeast strains are occasionally contaminated by or sometimes need co-cultivation with other microorganisms to improve yield or give the product unique taste and flavor. The co-culture of yeast strains and other microorganisms can be used to produce target products that require relative long biosynthetic pathways, thereby improving their production efficiency. Interactions between different microorganisms are complicated and, in some cases, are vital for microorganisms to improve their fermentation performances.

The goal of this Special Issue is to publish both recent innovative research results, as well as review papers on the fermentation performed by yeast strains, such as the production of chemicals and foods, the fermentation process, and attempts to improve the stress tolerance of yeast strains. Reviews and research papers on co-cultivation related interactions and social behaviors, microorganism co-existence, and environmental stresses-associated physiological changes that occur in the fermentation of S. cerevisiae are also of interest. If you would like to contribute a review paper, please contact one of the editors to discuss the topic relevance before submitting the manuscript.

Dr. Hao Li
Guest Editor

Manuscript Submission Information

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Keywords

  • yeast
  • fermentation
  • fermentation process
  • co-culture
  • stress tolerance
  • chemicals
  • foods
  • interaction between microorganisms
  • fermentation efficiency
  • metabolic engineering
  • strain development

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Published Papers (13 papers)

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Research

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16 pages, 1677 KiB  
Article
Utilization of Meat and Bone Meal for Yeast Fermentation to Produce Astaxanthin
by Sang Li and Yi Zheng
Fermentation 2023, 9(7), 630; https://doi.org/10.3390/fermentation9070630 - 3 Jul 2023
Cited by 1 | Viewed by 1378
Abstract
Meat and bone meal (MBM) is a product of the rendering industry, which is looking for high-value applications of rendered animal proteins (RAP). The objective of this research was to utilize MBM as a nitrogen source to produce astaxanthin (AX) by Xanthophyllomyces dendrorhous [...] Read more.
Meat and bone meal (MBM) is a product of the rendering industry, which is looking for high-value applications of rendered animal proteins (RAP). The objective of this research was to utilize MBM as a nitrogen source to produce astaxanthin (AX) by Xanthophyllomyces dendrorhous and quantify the bioavailability of MBM as a potential substitution of commercial nitrogen sources (i.e., yeast extract and peptone). To conduct yeast fermentation under the optimal glucose loading, the C/N ratio was optimized to achieve maximum AX content. MBM was hydrolyzed by using proteinase and alkaline (Ca(OH)2) for 4, 8, and 16 h with different enzyme and alkaline loadings to produce MBM hydrolysates (MBMHs). The MBMHs were directly fermented by X. dendrorhous under the optimum glucose concentration. Experimentally, the optimum medium contained 40 g/L glucose, 5 g/L peptone, and 3 g/L yeast extract, where AX content of 3.69 mg/g dry cell mass was achieved. MBMHs were used by X. dendrorhous as a nitrogen source, while fermentation with lyophilized MBMHs was generated using proteinase K. This resulted in a maximum AX content of 1.58 mg/g dry cell mass. This research exhibits the feasibility of using MBM as a nitrogen source to produce AX with X. dendrorhous. Full article
(This article belongs to the Special Issue Yeast - Fermentation)
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16 pages, 2101 KiB  
Article
Genomic Insight and Optimization of Astaxanthin Production from a New Rhodotorula sp. CP72-2
by Engkarat Kingkaew, Nisachon Tedsree, Sukanya Phuengjayaem, Pornchai Rojsitthisak, Boonchoo Sritularak, Worathat Thitikornpong, Somphob Thompho, Wuttichai Mhuantong and Somboon Tanasupawat
Fermentation 2023, 9(6), 501; https://doi.org/10.3390/fermentation9060501 - 24 May 2023
Cited by 4 | Viewed by 2087
Abstract
Astaxanthin is a carotenoid pigment extensively used in various industries. Rhodotorula sp. CP72-2, isolated from Calotropis gigantea, showed potential astaxanthin production. In this study, strain CP72-2 was identified as a putative new species in the genus Rhodotorula based on the 26S rRNA [...] Read more.
Astaxanthin is a carotenoid pigment extensively used in various industries. Rhodotorula sp. CP72-2, isolated from Calotropis gigantea, showed potential astaxanthin production. In this study, strain CP72-2 was identified as a putative new species in the genus Rhodotorula based on the 26S rRNA gene sequence (98% identity). It was first used as the microbial source for producing astaxanthin. Strain CP72-2 was screened for its astaxanthin production and was identified and quantified by High-Performance Liquid Chromatography (HPLC), Liquid Chromatography-Mass Spectrometry (LC-MS), and UV-Vis spectrophotometer. After a screening of astaxanthin production, various carbon sources, pH, temperature, and incubation period were evaluated for their effect on the astaxanthin production of strain CP72-2. Among the several experimental factors, the most efficient conditions for astaxanthin production were glucose (50 g/L), pH 4.5, 25 °C, and three days of cultivation. The assembly genome of strain CP72-2 has a total length of 21,358,924 bp and a GC content of 64.90%. The putative candidate astaxanthin biosynthesis-associated genes (i.e., CrtE, CrtYB, CrtI, CrtS, CrtR, CrtW, CrtO, and CrtZ) were found. This research presents the first report on the production and optimization of astaxanthin from strain CP72-2 and its genome analysis, focusing on the biotechnological potential of the astaxanthin producer. Full article
(This article belongs to the Special Issue Yeast - Fermentation)
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18 pages, 2853 KiB  
Article
Potential Capacity of Candida wangnamkhiaoensis to Produce Oleic Acid
by Alejandro Pérez-Rodríguez, César Mateo Flores-Ortiz, Griselda Ma. Chávez-Camarillo, Eliseo Cristiani-Urbina and Liliana Morales-Barrera
Fermentation 2023, 9(5), 443; https://doi.org/10.3390/fermentation9050443 - 7 May 2023
Cited by 4 | Viewed by 2173
Abstract
Oleic acid is increasingly required in many industries, causing the indiscriminate extension of land for the cultivation of certain agricultural products to extract their oil. The current contribution aimed to cultivate Candida wangnamkhiaoensis (CW) for the production of lipids and determine the profile [...] Read more.
Oleic acid is increasingly required in many industries, causing the indiscriminate extension of land for the cultivation of certain agricultural products to extract their oil. The current contribution aimed to cultivate Candida wangnamkhiaoensis (CW) for the production of lipids and determine the profile of fatty acids in these lipids. The lipid yield was compared in the yeast when using glucose or glycerol as the substrate, in both cases being over 24%. The main fatty acids in the oil derived from CW were oleic, palmitic, stearic, and linoleic acid. The fatty acid composition of the oil from CW was very similar to that of avocado oil and resembled that of olive oil and palm oil. The advantages of cultivating CW include its relatively high percentage of oleic acid and the balance of other fatty acids, its capacity to generate lipids in a short time (48–72 h), the controlled environment of production (versus the variability of the cultivation of agricultural products), and the relatively limited surface area required. CW shows potential as an alternative and economical source of oleic acid for the food, drug, cosmetics, lubricant, and biofuel industries, and does not require the alteration of large extensions of land. Full article
(This article belongs to the Special Issue Yeast - Fermentation)
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15 pages, 1023 KiB  
Article
Microbial Communities of Flor Velums and the Genetic Stability of Flor Yeasts Used for a Long Time for the Industrial Production of Sherry-like Wines
by Andrey V. Mardanov, Eugeny V. Gruzdev, Alexey V. Beletsky, Elena V. Ivanova, Maksim Yu. Shalamitskiy, Tatiana N. Tanashchuk and Nikolai V. Ravin
Fermentation 2023, 9(4), 367; https://doi.org/10.3390/fermentation9040367 - 9 Apr 2023
Cited by 3 | Viewed by 2188
Abstract
Flor yeast strains represent a specialized group of Saccharomyces cerevisiae yeasts used for the production of sherry-like wines by biological wine aging. We sequenced the genome of the industrial flor yeast strain I-329 from a collection of microorganisms for winemaking “Magarach” and the [...] Read more.
Flor yeast strains represent a specialized group of Saccharomyces cerevisiae yeasts used for the production of sherry-like wines by biological wine aging. We sequenced the genome of the industrial flor yeast strain I-329 from a collection of microorganisms for winemaking “Magarach” and the metagenomes of two flor velums based on this strain and continuously maintained for several decades. The winery uses two processes for the production of sherry-like wine: batch aging and a continuous process similar to the criaderas–solera system. The 18S rRNA gene profiling and sequencing of metagenomes of flor velums revealed the presence of the yeasts Pichia membranifaciens and Malassezia restricta in minor amounts along with the dominant S. cerevisiae I-329 flor yeast. Bacteria Oenococcus oeni and Lentilactobacillus hilgardii together accounted for approximately 20% of the velum microbiota in the case of a batch process, but less than 1% in the velum used in the continuous process. Collection strain I-329 was triploid for all chromosomes except diploid chromosomes I and III, while the copy numbers of all chromosomes were equal in industrial velums. A comparative analysis of the genome of strain I-329 maintained in the collection and metagenomes of industrial velums revealed only several dozens of single nucleotide polymorphisms, which indicates a long-term genetic stability of this flor yeast strain under the harsh conditions of biological wine aging. Full article
(This article belongs to the Special Issue Yeast - Fermentation)
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13 pages, 5294 KiB  
Article
Fermentation of Sweet Sorghum (Sorghum bicolor L. Moench) Using Immobilized Yeast (Saccharomyces cerevisiae) Entrapped in Calcium Alginate Beads
by Jeric Paul R. Cadiz, Rosalie P. Agcaoili, Roselle Y. Mamuad and Angelo Earvin Sy Choi
Fermentation 2023, 9(3), 272; https://doi.org/10.3390/fermentation9030272 - 10 Mar 2023
Cited by 5 | Viewed by 2903
Abstract
As the population grows, there is a need to address the continuous depletion of non-renewable energy sources and their negative effects on the environment. This led to a substantial assessment of possible innovations and raw materials to increase the volumetric productivity of alternative [...] Read more.
As the population grows, there is a need to address the continuous depletion of non-renewable energy sources and their negative effects on the environment. This led to a substantial assessment of possible innovations and raw materials to increase the volumetric productivity of alternative fuels to supply the energy needed worldwide. In addition to its environment-friendly properties, a biofuel derived from plant-based sources is also a sustainable material. For high ethanol production from plant-based biofuel, several techniques have been developed, including cell or enzyme immobilization. The key purposes of utilizing immobilized cells or enzymes are to improve bioreactor yield with upgraded enzyme establishment and to increase enzyme utilization. The fermentation of sweet sorghum extract to produce ethanol was conducted in this study, and it was found that the optimum sodium alginate concentration for immobilizing yeast is 3% w/v. It was also found that the free yeast has a shorter optimum fermentation period which is four days (96 h), in comparison with the immobilized yeast, which is five days (120 h). The immobilized yeast has a higher ethanol concentration produced and percent conversion compared to the free yeast. The immobilized yeast entrapped in calcium alginate beads permitted ten five-day (120 h) reuse cycles which are still in stable final ethanol concentration and percent conversion. Due to a lack of experimental support in the necessary condition (optimum level of the number of fermentation days and the concentration of sodium alginate) for the optimal ethanol yield from the extract of sweet sorghum, this study was conducted. This study also tried to address the global demand for ethanol by specifying the optimum conditions necessary for efficient fermentation, specifically for ethanol production using an extract from sweet sorghum. Furthermore, this experimental work serves as a basis for further investigations concerning ethanol production from Agri-based materials, such as sweet sorghum. Full article
(This article belongs to the Special Issue Yeast - Fermentation)
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11 pages, 2515 KiB  
Article
Influence of Long-Term Agar-Slant Preservation at 4 °C on the Recombinant Enzyme Activity of Engineered Yeast
by Xiao Liang, Ting Gong, Jing-Jing Chen, Tian-Jiao Chen, Jin-Ling Yang and Ping Zhu
Fermentation 2023, 9(2), 104; https://doi.org/10.3390/fermentation9020104 - 23 Jan 2023
Cited by 1 | Viewed by 6447
Abstract
Strain preservation to maintain stable vitality and the recombinant enzyme activity plays a crucial role in industrial fermentation. A Pichia pastoris strain is routinely stored at −80 °C in a glycerol vial and activated on an antibiotic-containing YPD agar plate before being used [...] Read more.
Strain preservation to maintain stable vitality and the recombinant enzyme activity plays a crucial role in industrial fermentation. A Pichia pastoris strain is routinely stored at −80 °C in a glycerol vial and activated on an antibiotic-containing YPD agar plate before being used for fermentation. Alternatively, the activated strain should be preserved in the agar slant at 2~4 °C (low-temperature storage) for a short period before use. To maximize the utilization of the low-temperature storage for fermentation, we evaluated this method by observing the capacity of both the vitality and the recombinant enzyme activity of the strain at different preservation durations. We found that engineered yeast could be preserved by low-temperature storage for at least 30 months without losing its vitality and biomass enzyme activity by the end of fermentation and could be directly used for the seed cultivation of fermentation, which is more time-saving than strain recovery from −80 °C in a glycerol vial. Moreover, the antibiotic added to the agar slant could be omitted if the heterologous gene was integrated into the host chromosome. Our approach may greatly elevate the production efficiency of the strain. Full article
(This article belongs to the Special Issue Yeast - Fermentation)
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18 pages, 2991 KiB  
Article
Growth Kinetics of Kazachstania unispora and Its Interaction with Lactic Acid Bacteria during Qymyz Production
by Askar Kondybayev, Nawel Achir, Christian Mestres, Ingrid Collombel, Caroline Strub, Joel Grabulos, Nurlan Akhmetsadykov, Aidana Aubakirova, Ulzhan Kamidinkyzy, Wijden Ghanmi and Gaukhar Konuspayeva
Fermentation 2023, 9(2), 101; https://doi.org/10.3390/fermentation9020101 - 23 Jan 2023
Cited by 2 | Viewed by 2505
Abstract
Qymyz is a traditional acidic and ethanolic beverage in central Asian countries made from mare milk fermentation with lactic acid bacteria (LAB) and yeasts. Modeling the growth of microorganisms during fermentation is one of the methods used to control the quality of fermented [...] Read more.
Qymyz is a traditional acidic and ethanolic beverage in central Asian countries made from mare milk fermentation with lactic acid bacteria (LAB) and yeasts. Modeling the growth of microorganisms during fermentation is one of the methods used to control the quality of fermented products. The objective of the study was, firstly, to model the growth kinetics of Kazachstania unispora found in qymyz, and, secondly, to understand their interaction with Lacticaseibacillus casei and Lactobacillus kefiri during the fermentation of mare milk. The K. unispora optimum values of pH and temperature were 4.81 ± 0.22 and 30.16 ± 0.53 °C, respectively, with an optimal growth rate (µopt) of 0.56 ± 0.02 h−1. K. unispora had an ethanol production rate of 6.1 × 10−8 mg·CFU−1. Growth, in terms of limiting substrates showed a lower Ks value for galactose at 0.13 ± 0.04 mg·mL−1 with µopt of 0.45 ± 0.01 h−1, while, for glucose, the Ks was 0.24 ± 0.03 mg·mL−1 with the same µopt. Cocultures of K. unispora were conducted with L. casei and L. kefiri in a synthetic medium and mare milk. The results showed that K. unispora growth was limited and, thus, its ethanol production capacity was inhibited. VOC analysis of mare milk fermented with the studied strains and their cocultures resulted in 37 major volatile compounds. Statistical analysis of the VOC profiles showed that K. unispora modulates the aroma production in coculture with LAB. Full article
(This article belongs to the Special Issue Yeast - Fermentation)
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16 pages, 2037 KiB  
Article
Untargeted Metabolomics Combined with Metabolic Flux Analysis Reveals the Mechanism of Sodium Citrate for High S-Adenosyl-Methionine Production by Pichia pastoris
by Wentao Xu, Feng Xu, Weijing Song, Le Dong, Jiangchao Qian and Mingzhi Huang
Fermentation 2022, 8(12), 681; https://doi.org/10.3390/fermentation8120681 - 27 Nov 2022
Cited by 3 | Viewed by 2163
Abstract
S-adenosyl-methionine (SAM) is crucial for organisms to maintain some physiological functions. However, the inconsistency between high L-methionine feeding rate and yield during SAM production at an industrial scale and its metabolic mechanism have not been elucidated. Here, the cellular metabolic mechanism of feeding [...] Read more.
S-adenosyl-methionine (SAM) is crucial for organisms to maintain some physiological functions. However, the inconsistency between high L-methionine feeding rate and yield during SAM production at an industrial scale and its metabolic mechanism have not been elucidated. Here, the cellular metabolic mechanism of feeding sodium citrate to the Pichia pastoris (P. pastoris) G12’/AOX-acs2 strain to enhance SAM production was investigated using untargeted metabolomics and metabolic flux analysis. The results indicated that the addition of sodium citrate has a facilitative effect on SAM production. In addition, 25 metabolites, such as citrate, cis-aconitate, and L-glutamine, were significantly up-regulated, and 16 metabolites, such as glutathione, were significantly down-regulated. Furthermore, these significantly differential metabolites were mainly distributed in 13 metabolic pathways, such as the tricarboxylic acid (TCA) cycle. In addition, the metabolic fluxes of the glycolysis pathway, pentose phosphate pathway, TCA cycle, and glyoxylate pathway were increased by 20.45–29.32%, respectively, under the condition of feeding sodium citrate compared with the control. Finally, it was speculated that the upregulation of dihydroxyacetone level might increase the activity of alcohol oxidase AOX1 to promote methanol metabolism by combining metabolomics and fluxomics. Meanwhile, acetyl coenzyme A might enhance the activity of citrate synthase through allosteric activation to promote the flux of the TCA cycle and increase the level of intracellular oxidative phosphorylation, thus contributing to SAM production. These new insights into the L-methionine utilization for SAM biosynthesis by systematic biology in P. pastoris provides a novel vision for increasing its industrial production. Full article
(This article belongs to the Special Issue Yeast - Fermentation)
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15 pages, 2744 KiB  
Article
β-Farnesene Production from Low-Cost Glucose in Lignocellulosic Hydrolysate by Engineered Yarrowia lipolytica
by Haoran Bi, Chenchen Xv, Changsheng Su, Pan Feng, Changwei Zhang, Meng Wang, Yunming Fang and Tianwei Tan
Fermentation 2022, 8(10), 532; https://doi.org/10.3390/fermentation8100532 - 12 Oct 2022
Cited by 11 | Viewed by 3718
Abstract
β-Farnesene is value-added acyclic volatile sesquiterpene with wide applications in energy, industry, and agriculture. Producing high-value-added compounds from low-cost renewable feedstocks in engineered microbial cell factories is an environmentally friendly and economical process for β-farnesene biosynthesis. In this study, the potential for using [...] Read more.
β-Farnesene is value-added acyclic volatile sesquiterpene with wide applications in energy, industry, and agriculture. Producing high-value-added compounds from low-cost renewable feedstocks in engineered microbial cell factories is an environmentally friendly and economical process for β-farnesene biosynthesis. In this study, the potential for using engineered Yarrowia lipolytica to produce β-farnesene from lignocellulosic hydrolysate as the carbon source was investigated. An efficient biosynthetic pathway for β-farnesene production was established via iterative enhancement of multiple genes based on the high endogenous acetyl-CoA flux in Yarrowia lipolytica. Overexpression of mevalonate pathway genes and screening of β-farnesene synthase resulted in a β-farnesene titer of 245 mg L−1 in glucose media. Additional copies of mevalonate pathway genes and enhanced expression of HMG-CoA reductase and β-farnesene synthase further increased the titer of β-farnesene to 470 mg L−1. In addition, by combining metabolic engineering strategies using the lignocellulosic hydrolysate utilization strategy, the addition of Mg2+ promoted the production of β-farnesene, and the best-performing strain produced 7.38 ± 0.24 g L−1 β-farnesene from lignocellulosic hydrolysate media in a 2 L fermenter after 144 h. This study shows great potential for the sustainable production of β-farnesene from lignocellulosic biomass via engineered Yarrowia lipolytica. Full article
(This article belongs to the Special Issue Yeast - Fermentation)
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15 pages, 2971 KiB  
Article
Self-Produced Hydrogen Sulfide Improves Ethanol Fermentation by Saccharomyces cerevisiae and Other Yeast Species
by Emilio Espinoza-Simón, Paola Moreno-Álvarez, Elias Nieto-Zaragoza, Carolina Ricardez-García, Emmanuel Ríos-Castro, Salvador Uribe-Carvajal and Francisco Torres-Quiroz
Fermentation 2022, 8(10), 505; https://doi.org/10.3390/fermentation8100505 - 1 Oct 2022
Cited by 1 | Viewed by 2966
Abstract
Hydrogen sulfide (H2S) is a gas produced endogenously in organisms from the three domains of life. In mammals, it is involved in diverse physiological processes, including the regulation of blood pressure and its effects on memory. In contrast, in unicellular organisms, [...] Read more.
Hydrogen sulfide (H2S) is a gas produced endogenously in organisms from the three domains of life. In mammals, it is involved in diverse physiological processes, including the regulation of blood pressure and its effects on memory. In contrast, in unicellular organisms, the physiological role of H2S has not been studied in detail. In yeast, for example, in the winemaking industry, H2S is an undesirable byproduct because of its rotten egg smell; however, its biological relevance during fermentation is not well understood. The effect of H2S in cells is linked to a posttranslational modification in cysteine residues known as S-persulfidation. In this paper, we evaluated S-persulfidation in the Saccharomyces cerevisiae proteome. We screened S-persulfidated proteins from cells growing in fermentable carbon sources, and we identified several glycolytic enzymes as S-persulfidation targets. Pyruvate kinase, catalyzing the last irreversible step of glycolysis, increased its activity in the presence of a H2S donor. Yeast cells treated with H2S increased ethanol production; moreover, mutant cells that endogenously accumulated H2S produced more ethanol and ATP during the exponential growth phase. This mechanism of the regulation of metabolism seems to be evolutionarily conserved in other yeast species, because H2S induces ethanol production in the pre-Whole-Genome Duplication species Kluyveromyces marxianus and Meyerozyma guilliermondii. Our results suggest a new role of H2S in the regulation of the metabolism during fermentation. Full article
(This article belongs to the Special Issue Yeast - Fermentation)
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16 pages, 2931 KiB  
Article
Metabolic Engineering of Saccharomyces cerevisiae for Production of Fragrant Terpenoids from Agarwood and Sandalwood
by Peerada Promdonkoy, Warasirin Sornlek, Thanchanok Preechakul, Sutipa Tanapongpipat and Weerawat Runguphan
Fermentation 2022, 8(9), 429; https://doi.org/10.3390/fermentation8090429 - 29 Aug 2022
Cited by 9 | Viewed by 3728
Abstract
Sandalwood and agarwood essential oils are rare natural oils comprising fragrant terpenoids that have been used in perfumes and incense for millennia. Increasing demand for these terpenoids, coupled with difficulties in isolating them from natural sources, have led to an interest in finding [...] Read more.
Sandalwood and agarwood essential oils are rare natural oils comprising fragrant terpenoids that have been used in perfumes and incense for millennia. Increasing demand for these terpenoids, coupled with difficulties in isolating them from natural sources, have led to an interest in finding alternative production platforms. Here, we engineered the budding yeast Saccharomyces cerevisiae to produce fragrant terpenoids from sandalwood and agarwood. Specifically, we constructed strain FPPY005_39850, which overexpresses all eight genes in the mevalonate pathway. Using this engineered strain as the background strain, we screened seven distinct terpene synthases from agarwood, sandalwood, and related plant species for their activities in the context of yeast. Five terpene synthases led to the production of fragrant terpenoids, including α-santalene, α-humulene, δ-guaiene, α-guaiene, and β-eudesmol. To our knowledge, this is the first demonstration of β-eudesmol production in yeast. We further improved the production titers by downregulating ERG9, a key enzyme from a competing pathway, as well as employing enzyme fusions. Our final engineered strains produced fragrant terpenoids at up to 101.7 ± 6.9 mg/L. We envision our work will pave the way for a scalable route to these fragrant terpenoids and further establish S. cerevisiae as a versatile production platform for high-value chemicals. Full article
(This article belongs to the Special Issue Yeast - Fermentation)
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Review

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25 pages, 3296 KiB  
Review
Biosurfactants Produced by Yeasts: Fermentation, Screening, Recovery, Purification, Characterization, and Applications
by Natalia de Andrade Teixeira Fernandes, Luara Aparecida Simões and Disney Ribeiro Dias
Fermentation 2023, 9(3), 207; https://doi.org/10.3390/fermentation9030207 - 22 Feb 2023
Cited by 12 | Viewed by 5081
Abstract
The demand for biosurfactants (BS) produced by yeast for use in industrial processes and products is increasing. Therefore, there has been an increase in the number of publications related to characterization of surfactant compounds produced by yeasts generally recognized as safe (GRAS), which [...] Read more.
The demand for biosurfactants (BS) produced by yeast for use in industrial processes and products is increasing. Therefore, there has been an increase in the number of publications related to characterization of surfactant compounds produced by yeasts generally recognized as safe (GRAS), which has enabled their application in several industries, including the pharmaceutical and food industries. However, some of these studies use techniques that are not accurate or are no longer essential because of advancements in new technologies. Given the industrial importance of yeasts and their potential to produce BS, this study reviews the production of BS by this microorganism and the most recent industrial applications of BS. It also critically reviews a wide range of techniques used in screening of BS-producing strains, as well as those used in recovery, purification, and characterization of these surfactant compounds produced by yeasts. This review introduces diverse methodologies that are indispensable for the study of BS produced by yeast in an effort to advance BS design, synthesis, and application and introduces new perspectives in the research of these compounds to overcome the obstacles present in this field. Full article
(This article belongs to the Special Issue Yeast - Fermentation)
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17 pages, 1005 KiB  
Review
Recent Advances in Multiple Strategies for the Synthesis of Terpenes by Engineered Yeast
by Limeng Yang, Huan Liu, Yuhan Jin, Junfeng Liu, Li Deng and Fang Wang
Fermentation 2022, 8(11), 615; https://doi.org/10.3390/fermentation8110615 - 8 Nov 2022
Cited by 12 | Viewed by 4378
Abstract
Terpenes are an important class of natural secondary metabolites with a wide range of applications in food, pharmaceuticals, and biofuels. Currently, the traditional production methods of terpenes almost depend on plant extraction and chemical conversion. The plant extraction method consumes a lot of [...] Read more.
Terpenes are an important class of natural secondary metabolites with a wide range of applications in food, pharmaceuticals, and biofuels. Currently, the traditional production methods of terpenes almost depend on plant extraction and chemical conversion. The plant extraction method consumes a lot of natural resources and makes it difficult to separate the target compound from the extractives, while the chemical conversion method has a complex synthesis route and leads to severe environmental pollution. Compared to plant extraction and chemical conversion methods, the microbial synthesis method has the advantages of preferable sustainability, low production cost and environmental friendliness, and is a potential way to achieve efficient terpenes production in the future. Yeast is a conventional platform for bio-chemical production and is also engineered to synthesize terpenes due to their abundant intracellular acetyl-CoA, high metabolic flux of the MVA pathway, high local concentrations of substrates and enzymes, and fewer by-products. At present, a variety of terpenes including α-farnesene, squalene, limonene, β-carotene have been successfully synthesized by the engineered yeast via the application of multiple strategies. This work summarized the progress of research on these strategies conducted in the synthesis of terpenes from several aspects, including the adaptive screening and expression of terpene synthases, the regulation of synthesis pathways, and the application of intracellular compartmentalized expression strategy. The perspectives and challenges were also discussed, from which it was hoped that some useful views for future research on the synthesis of terpenes in yeast would be provided. Full article
(This article belongs to the Special Issue Yeast - Fermentation)
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