Submit to Agronomy Review for Agronomy Propose a Special Issue

Journal Menu

Journal Browser

► Journal Browser

Agricultural Valorization of Agro-Industrial By-Products: From Waste to Value

Print Special Issue Flyer
Special Issue Editors
Special Issue Information
Keywords
Benefits of Publishing in a Special Issue
Published Papers

A special issue of Agronomy (ISSN 2073-4395). This special issue belongs to the section "Farming Sustainability".

Deadline for manuscript submissions: closed (30 April 2023) | Viewed by 25591

Share This Special Issue

Special Issue Editors

Dr. David Correa-Galeote

E-Mail Website1 Website2
Guest Editor

Department of Microbiology, University of Granada, 18071 Granada, Spain
Interests: environmental microbiology; wastewater treatment; microbial ecology; correlation networks; mixed microbial culture (MMC)
Special Issues, Collections and Topics in MDPI journals

Dr. Antonio Serrano

E-Mail Website
Guest Editor

Department of Microbiology, University of Granada, 18071 Granada, Spain
Interests: environmental microbiology; wastewater treatment; microbial ecology; anaerobic digestion
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear Colleagues,

The continuously growing world population corresponds with the increasing demand for food worldwide. To meet this requirement, the agriculture industry has attempted to profoundly enhance crop production. However, these farming techniques, mainly the abuse and misuse of chemical fertilizers, have led to a general decline in soil quality, resulting in a vicious circle that accelerates the deterioration of soil quality and diminishes the worldwide agricultural yield. In addition, the overreliance on inorganic fertilizers decreases the abundance, accessibility, or uptake of soil nutrients, compromising the functionality of the native plant growth-promoting rhizobacteria (PGPR).

On another front, the increasing production of industrial organic wastes and other residues makes their disposal and treatment particularly complex, resulting in major economic, social, and environmental challenges. Nevertheless, different industrial wastes are often enriched in fatty acids, volatile organic compounds, proteins, and carbohydrates, which can be employed as a crop nutrition source and a stimulant for plant growth-promoting microbiome without damaging the environment. Therefore, harmful industrial wastes could improve soil fertility, plant stress tolerance, crop productivity, and balanced nutrient cycling. Moreover, their agricultural utilization is a novel way of transforming them into value-added co-products, allowing for the implementation of the circular economy concept to the agricultural sector.

This Special Issue aims to focus on the novel utilization of industrial by-products and wastes as promoters of the fertility and nutrient status of soil as alternatives to the abuse and misuse of chemical fertilizers. We are open to receiving novel research, reviews, and opinion articles covering all aspects of using newly developed bio-fertilizers derived from the industrial co-products to stretch the native PGPR microbiome. Moreover, improved farming techniques, including new eco-friendly compounds, to achieve the increasing worldwide demand for food will be an essential part of this Special Issue. Finally, agronomic studies assessing these co-products as PGPR inoculants in sustainable agriculture are also welcome.

Dr. David Correa-Galeote
Dr. Antonio Serrano
Guest Editors

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All submissions that pass pre-check are peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Agronomy is an international peer-reviewed open access monthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2600 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

agro-industrial residues
agro-wastes
food by-products
novel technology
recovery (proteins, dietary fibers, antioxidants, and new fertilizers et al.) from plant origin by-products
valorization of industrial waste and crop residues with potential
application
biomass conversion
enhancing yield and quality of crops
plague control and stress prevention
new sources of PGRP
new microbial inoculants
sustainable agriculture

Benefits of Publishing in a Special Issue

Ease of navigation: Grouping papers by topic helps scholars navigate broad scope journals more efficiently.
Greater discoverability: Special Issues support the reach and impact of scientific research. Articles in Special Issues are more discoverable and cited more frequently.
Expansion of research network: Special Issues facilitate connections among authors, fostering scientific collaborations.
External promotion: Articles in Special Issues are often promoted through the journal's social media, increasing their visibility.
e-Book format: Special Issues with more than 10 articles can be published as dedicated e-books, ensuring wide and rapid dissemination.

Further information on MDPI's Special Issue polices can be found here.

Published Papers (13 papers)

Download All Papers

Order results

Result details

Show export options Show export options

Select all

Export citation of selected articles as:

Research

Jump to: Review

15 pages, 1910 KiB

Open AccessArticle

Acid Hydrothermal Amendment of Grape Wine Pomace: Enhancement of Phenol and Carbohydrate Co-Solubilization

by Antonio Serrano, Paola Díaz-Navarrete, Roberto Mora, Gustavo Ciudad, Juan Carlos Ortega and Fernanda Pinto-Ibieta

Agronomy 2023, 13(6), 1501; https://doi.org/10.3390/agronomy13061501 - 30 May 2023

Cited by 2 | Viewed by 1400

Abstract

Byproducts from the winery industry contain many bioactive compounds that are considered high-value-added compounds. White grape pomace (GP) is rich in carbohydrates; consequently, it can be used as a raw material for subsequent bioprocesses. In the present study, low-temperature hydrothermal treatments were carried out using different operational conditions regarding temperature (65–95 °C), time (120–240 min), and sulfuric acid addition at various concentrations (5–15% v/v). The results showed that by using a temperature of 65 °C, a period of 120 min, and 15% (v/v) of H₂SO₄, it was possible to obtain a liquid phase rich in phenols and carbohydrates, with total phenol compounds corresponding to 2113 ± 140 mg of gallic acid/kg GP and composed mainly of 3-hydroxytyrosol (1330 ± 22 mg/kg GP). In parallel, carbohydrate solubilization reached 245 g glucose/kg GP. These results demonstrate the promising potential of hydrothermally treated grape pomace as raw material for biorefinery processes. Full article

(This article belongs to the Special Issue Agricultural Valorization of Agro-Industrial By-Products: From Waste to Value)

► Show Figures

Figure 1

12 pages, 318 KiB

Open AccessArticle

Use of Compost Based on Invasive Algae Rugulopteryx okamurae as a Peat Alternative in Nursery Growing Media

by Francesca Berti, María del Carmen Salas-Sanjuán, Francisco Hernández-López, Amelia Correa-Bustos and María Luz Segura-Pérez

Agronomy 2023, 13(4), 948; https://doi.org/10.3390/agronomy13040948 - 23 Mar 2023

Cited by 4 | Viewed by 2023

Abstract

The invasion of the macroalgae Rugulopteryx okamurae is causing several environmental and economic problems along Spanish Mediterranean coasts. The use of composts based on R. okamurae as a peat alternative in nursery production could be a valid alternative for the exploitation of this organic material. The present study evaluated three different composts as peat substitutes in potting media to grow tomato seedlings: compost of R. okamurae, compost of green horticultural residues (two-thirds) and R. okamurae (one-third), compost of garden pruning residues (two-thirds) and R. okamurae (one-third). Each compost was used to formulate two different substrates to reduce the use of peat (40% compost, 40% peat, 20% perlite) or entirely substitute it (80% compost, 20% perlite), using a control treatment with 80% peat and 20% perlite. Only the control treatment received mineral fertigation during the trial. The results showed that the high initial electrical conductivity and ion concentration were remarkably reduced thanks to the fast leaching of salt that occurred with customary irrigation. Generally, compost-based treatments allowed us to obtain tomato seedlings with satisfactory morphological parameters. The substrates that contained 40% compost of R. okamurae or a compost of garden pruning residues and R. okamurae led to the best results in term of seedling parameters. It is therefore concluded that composts based on R. okamuare could be used as a seedling growing medium for the valorization of algae. Full article

(This article belongs to the Special Issue Agricultural Valorization of Agro-Industrial By-Products: From Waste to Value)

12 pages, 689 KiB

Open AccessArticle

Aquaculture Sludge as Co-Substrate for Sustainable Olive Mill Solid Waste Pre-Treatment by Anthracophyllum discolor

by Michael Araneda, Fernanda Pinto-Ibieta, Xiaofan Xu, Olga Rubilar, Fernando G. Fermoso and Gustavo Ciudad

Agronomy 2023, 13(3), 724; https://doi.org/10.3390/agronomy13030724 - 28 Feb 2023

Viewed by 1831

Abstract

Olive mill solid waste (OMSW) is an agro-industrial waste that has a high content of recalcitrant lignocellulose, which can adversely affect the environment. This study aimed to evaluate the phenol and lignin removal and the enzyme activity involved in the biological pre-treatment of OMSW supplemented with aquaculture sludge (AS) as an external nitrogen source by Anthracophyllum discolor. The highest lignin removal and enzymatic activity performance was obtained in the mixture of OMSW and AS prepared at a C/N ratio 45. In these conditions, the pre-treatment could remove 66% of lignin and 68% of phenols in the solid phase and 56% of phenols in the liquid phase and the maximum activity of laccase, manganese peroxidase and manganese independent peroxidase were of 10, 289 and 75 U L⁻¹ in 25, 30, and 15 days of pre-treatment, respectively. These results propose that the addition of AS as a co-substrate for adjusting the C/N ratio allows a 41 and 141% increase in lignin removal and manganese peroxidase activity respectively, enabling the treatment of both OMSW and AS wastes and the possible recovery of an enzymatic extract of biotechnological interest. Full article

(This article belongs to the Special Issue Agricultural Valorization of Agro-Industrial By-Products: From Waste to Value)

► Show Figures

Figure 1

15 pages, 2420 KiB

Open AccessArticle

Crop Nitrogen Fertilization Schedule in Bread Wheat Affects the Mechanical Performances of Thermoplastic Films Obtained by Plasticization of Flours

by Paolo Benincasa, Franco Dominici, Francesca Luzi, Catia Governatori, Laura Gazza, Elena Galassi, Giacomo Tosti and Debora Puglia

Agronomy 2023, 13(3), 697; https://doi.org/10.3390/agronomy13030697 - 27 Feb 2023

Cited by 1 | Viewed by 1621

Abstract

Recent research has investigated the plasticization of wheat flour as a non-food alternative application. In this work, we analyzed the performances of thermoplastic films obtained using flours of two bread wheat cultivars (Bologna and Bora) grown in fall–spring under four nitrogen (N) fertilization treatments: (1) continuously well-N-fed (N300 = 300 kg N ha⁻¹, split throughout the growth cycle); (2) N-fed only very early (N60-0 = 60 kg N ha⁻¹, just one month after sowing); (3) N-fed only extremely late (N0-120 = 120 kg N ha⁻¹ at pollination); (4) unfertilized control (N0). Flours were characterized for glutenin and gliadin fractions, Chopin’s alveograph parameters, Field Emission Scanning Electron Microscopy (FESEM) images, and thermogravimetric analysis (TGA), while films were evaluated for mechanical properties (tensile strength at break, σ_b; elongation at break, ε_b; Young’s modulus, E) and FESEM images. Differences among treatments for absolute and relative abundances of gluten fractions and alveographic parameters were extremely marked and gave rise to differences in tensile properties of thermoplastic films. Within each cultivar, the ranking of treatments for ε_b values was N0 > N60-0 > N0-120 > N300. Thus, ε_b was inversely correlated with crop N availability and total gluten content of the flour. The σ_b was less variable among N treatments; however, in both cultivars, it was high in N0 and N300 and appreciably lower in N0-120. Overall, the best mechanical performances were obtained with flours from crops not subjected to imbalances in N nutrition (N0, N300). Our work demonstrates that bioplastic engineering needs to take into consideration the variability of biological source material like that caused by different crop N availability. Full article

(This article belongs to the Special Issue Agricultural Valorization of Agro-Industrial By-Products: From Waste to Value)

► Show Figures

Figure 1

11 pages, 309 KiB

Open AccessEditor’s ChoiceArticle

The Effect of Babassu Industry By-Products as an Alternative Feed for Dairy Cows

by Anderson Zanine, Cledson De Sá, Daniele Ferreira, Henrique Parente, Michelle Parente, Edson Mauro Santos, Rosane Rodrigues, Francisco Naysson Santos, Anny Graycy Lima, Ivo Alexandre Cunha, Francisca Claudia de Sousa, Renata Costa, Danillo Pereira, Paloma Gabriela Gomes and João Ricardo Dórea

Agronomy 2023, 13(2), 491; https://doi.org/10.3390/agronomy13020491 - 8 Feb 2023

Cited by 5 | Viewed by 1790

Abstract

The objective of this study was to evaluate the fermentative characteristics, chemical composition, and in vitro digestibility of a total mixed ration silage containing two babassu by-products, starchy flour and babassu cake. The treatments were distributed in a completely randomised design containing four treatments and five replications. The treatments consisted of corn silage, corn silage based on the standard corn and soybean diet, corn silage with babassu flour, and corn silage with babassu cake. No significant difference was observed in the pH values (p = 0.256) for the studied silages. Higher values for dry matter recovery were observed for the silages of the total diets. The corn silage presented lower lactic acid production (55.15 g/kg DM) and acetic acid (11.54 g/kg DM) in relation to the total ration silages. The inclusion of babassu by-products increased the dry matter (p < 0.001), crude protein (p < 0.001), and total digestible nutrient content (p < 0.001) in the total ration silages. Silage in the form of the total ration containing regional babassu by-products improved the fermentative profile of the silages and the nutritional value of the diets, endowing them with potential for use as a feed alternative for dairy cattle. Full article

(This article belongs to the Special Issue Agricultural Valorization of Agro-Industrial By-Products: From Waste to Value)

12 pages, 312 KiB

Open AccessArticle

Corn Silage as a Total Diet with by-Products of the Babassu Agroindustry in the Feed of Confined Ruminants

by Cledson Sá, Anderson Zanine, Daniele Ferreira, Henrique Parente, Michelle Parente, Edson Mauro Santos, Anny Graycy Lima, Francisco Naysson Santos, Danillo Pereira, Francisca Claudia de Sousa, Renata Costa, Carlos Rodolfo Castro, Guilherme Ribeiro Alves and João Ricardo Dórea

Agronomy 2023, 13(2), 417; https://doi.org/10.3390/agronomy13020417 - 31 Jan 2023

Cited by 3 | Viewed by 1741

Abstract

This study aimed to evaluate the chemical composition of total ration silage (TRS) containing two babassu by-products to replace the corn. The silages were formulated to meet the requirements of sheep for an average daily gain of 200 g/day. A completely randomized experimental design was used with four treatments and five replications. The treatments consisted of CS: Corn silage (Control); TRSS: Corn silage with corn and soybean meal; TRSF: Total ration silage with babassu mesocarp flour; and TRSC: Total feed silage with babassu cake. The chemical composition of the silages had a significant difference (p < 0.05) for all variates. There was a significant difference (p < 0.001) for gas (LG, p < 0.001) and effluent losses (LE, p < 0.001), dry matter recovery (DMR, p < 0.001), buffer capacity (BC, p < 0.001), lactic acid (LA, p < 0.001), butyric acid (BA, p < 0.001), lactic acid/fermentation products (LA:FP, p < 0.001), and ammoniacal nitrogen (NH₃-N, p < 0.001). The babassu by-products can replace ground corn by up to 50% in total ration silage and improve the fermentation profile and nutritional value of the silage, meeting the nutritional requirements of finishing sheep. Full article

(This article belongs to the Special Issue Agricultural Valorization of Agro-Industrial By-Products: From Waste to Value)

14 pages, 2305 KiB

Open AccessArticle

Accumulation of Volatile Fatty Acids from Hydrothermally Treated Strawberry Extrudate through Anaerobic Fermentation at Different pH Values

by Antonio Serrano, Egidio Russo, Blanca Chaves-Quesada, Juan Cubero-Cardoso, Ángeles Trujillo-Reyes, Giovanni Esposito, Xiaofan Xu and Fernando G. Fermoso

Agronomy 2023, 13(1), 120; https://doi.org/10.3390/agronomy13010120 - 30 Dec 2022

Cited by 1 | Viewed by 1413

Abstract

The accumulation of volatile fatty acids (VFAs) through the anaerobic fermentation of organic waste, such as strawberry extrudate, is proposed for this work. A hydrothermal treatment was carried out, and it was proposed to break the complex matrix of the strawberry extrudate to favour the hydrolysis stage of the anaerobic digestion process. The production of volatile fatty acids from treated and untreated strawberry was evaluated by adjusting the pH to 5 and 9. After the hydrothermal treatment of the strawberry extrudate, an increase in the solubilisation of organic matter, such as sugars and phenols, was observed. In the production of VFAs by means of anaerobic digestion of the pretreated strawberry extrudate, a significant increase in the accumulation of volatile fatty acids was demonstrated at a pH of 9 with respect to the untreated strawberry extrudate. In addition, the operational pH also had a strong effect on the individual VFA profile. A stream enriched in acetic acid was obtained at a pH of 9 (around 65% of the VFAs), whereas the operation at a pH of 5 resulted in a more complex composition with a high percentage of propionic acid (29% of the VFAs). Full article

(This article belongs to the Special Issue Agricultural Valorization of Agro-Industrial By-Products: From Waste to Value)

► Show Figures

Figure 1

12 pages, 2327 KiB

Open AccessArticle

Vermicomposting of Lavender Waste: A Biological Laboratory Investigation

by Miguel Ángel González-Moreno, Beñat García Gracianteparaluceta, Sara Marcelino Sádaba, Eduardo Prieto Cobo and Andrés Seco Meneses

Agronomy 2022, 12(12), 2957; https://doi.org/10.3390/agronomy12122957 - 25 Nov 2022

Cited by 6 | Viewed by 2496

Abstract

In the present work, lavender waste, a residue of the essential oil extract industry, was used to feed Eisenia andrei with mature horse manure at ratios of 0:100, 25:75, 50:50, 75:25 and 100:0 on dry weight basis. Vermicomposting was carried out for 70 days in laboratory conditions. Biological parameters such as population build-up, total biomass, mortality and cocoon production were observed and measured. Increasing concentrations of waste affected positively the growth and reproduction of worms in a significant way. The 100% lavender waste combination showed the best cocoon production and even tripled their biomass in the first week. A seed germination test was also made, where no evidence of toxicity was found. The germination index range was, in general terms, above 100. The results indicated that the earthworm E. andrei was able to transform lavender waste into compost and thus play a major role in industrial waste management and apply circular economy. Full article

(This article belongs to the Special Issue Agricultural Valorization of Agro-Industrial By-Products: From Waste to Value)

► Show Figures

Figure 1

15 pages, 1732 KiB

Open AccessArticle

Application of Spent Sun Mushroom Substrate in Substitution of Synthetic Fertilizers at Maize Topdressing

by Lucas da Silva Alves, Cinthia Elen Cardoso Caitano, Samuel Ferrari, Wagner Gonçalves Vieira Júnior, Reges Heinrichs, Bruno Rafael de Almeida Moreira, Arturo Pardo-Giménez and Diego Cunha Zied

Agronomy 2022, 12(11), 2884; https://doi.org/10.3390/agronomy12112884 - 18 Nov 2022

Cited by 5 | Viewed by 2189

Abstract

Synthetic fertilization can increase maize yields, but also cause environmental impacts, as well as increasing production costs and food security risks. Sun mushroom (Agaricus subrufescens) is an important Brazilian fungus used to generate large amounts of spent mushroom substrate. This residue can be used for maize fertilization, but little is known about its ideal application rates to reduce maize dependence on synthetic fertilizers. Therefore, this study aimed to evaluate the agronomic performance of a maize crop under different combinations of synthetic fertilizers and two different spent mushroom substrate doses. The experiment was carried out in pots and evaluated maize germinate and biometric parameters, as well as soil and leaf chemical characteristics. The results showed that residue application increased maize germination and Emergence Speed Index. Regarding the maize biometric parameters, height, stem diameter, shoot fresh and dry masses, and leaf area were superior for residue with synthetic fertilization at sowing only at higher doses. Moreover, residue with synthetic fertilization at sowing proved to be more relevant for maize growth according to canonical discriminant analysis. In terms of nutrients, the use of spent mushroom substrate increased significantly leaf P, K, and S levels and mainly K content in the soil, justifying non-application at maize topdressing. Full article

(This article belongs to the Special Issue Agricultural Valorization of Agro-Industrial By-Products: From Waste to Value)

► Show Figures

Figure 1

13 pages, 2291 KiB

Open AccessArticle

Biotransformation of Agricultural Wastes into Lovastatin and Optimization of a Fermentation Process Using Response Surface Methodology (RSM)

by Sadia Javed, Muhammad Azeem, Saqib Mahmood, Khalid Mashay Al-Anazi, Mohammad Abul Farah, Sajad Ali and Baber Ali

Agronomy 2022, 12(11), 2848; https://doi.org/10.3390/agronomy12112848 - 15 Nov 2022

Cited by 4 | Viewed by 2255

Abstract

Lovastatin is a competitive inhibitor of the enzyme 3-hydroxy-3-methyl-glutaryl-CoA reductase (HMG-CoA Reductase). The HMG-CoA reductase is responsible for the production of mevalonate by the reduction of HMG-CoA. It is a rate-limiting step in the production of cholesterol. The current study demonstrates the production of lovastatin from an ethidium bromide mutated strain of Aspergillus terreus ATE-120 (saprophytic fungus) that is grown on 1–3% NaOH pretreated substrate of sugar cane bagasse (Saccharum officinarum L.). For the hyperproduction of lovastatin, different optimization parameters such as temperature, pH, inoculum size, fermentation period, and inoculum age were mentioned and analyzed via response surface methodology. The RSM results indicate that the maximum lovastatin yield (156.43 mg/L) was predicted at a 5.5 pH, 35 °C temperature, 4 mL inoculum size, 36 h inoculum age, and 48 h fermentation via solid state fermentation. According to these results, the effect of pH had a significant effect on lovastatin production, while other parameters had an insignificant effect, and coefficients of determination (R²) having a value of 77.24% indicates the goodness of the proposed model. The structure of the obtained drug was confirmed by nuclear magnetic resonance. Moreover, an X-ray diffraction analysis of the sample was carried out to characterize the physical form of the lovastatin. It can be concluded from the above study that the maximum yield of the drug can be found via RSM and that the selected strain (Aspergillus terreus ATE-120) has good potential for lovastatin production through solid-state fermentation. Full article

(This article belongs to the Special Issue Agricultural Valorization of Agro-Industrial By-Products: From Waste to Value)

► Show Figures

Figure 1

12 pages, 2337 KiB

Open AccessArticle

Optimization of Ultrasound-Assisted Extraction from Young Coconut Mesocarp in the Rapid Extraction of Phenolic Compounds and Antioxidant Activity

by Lulum Leliana, Widiastuti Setyaningsih, Miguel Palma, Supriyadi Supriyadi and Umar Santoso

Agronomy 2022, 12(11), 2798; https://doi.org/10.3390/agronomy12112798 - 10 Nov 2022

Cited by 4 | Viewed by 2067

Abstract

Coconut (Cocos nucifera) fruit has attracted consumer interest due to its health benefits, especially the consumption of coconut water produced from 6–7-month-old coconut fruit. Consequently, by-products from young coconut fruit are also being expanded, including coconut mesocarp containing phenolic compounds. Therefore, this study aimed to provide new applications for young coconut mesocarp wastes. Specifically, optimizing the ultrasound-assisted extraction (UAE) of phenolic compounds from coconut mesocarp using a Box–Behnken design in conjunction with response surface methodology (RSM). The effects of three extraction variables, such as temperature (10–70 °C), solvent-to-sample ratio (20:1–10:1 mL g⁻¹), and pulse duty cycle (0.4–1.0 s⁻¹) were examined on the level of total phenolic content (TPC) and antioxidant activity of the extract. Subsequently, the optimum UAE condition was predicted using RSM models with coefficients of determination (R²) higher than 0.94, low prediction errors (less than 2.34), and non-significant lack-of-fit values (p < 0.05) for the two responses. Extraction time was evaluated through kinetic (5 to 25 min) studies applying the optimum extraction temperature (70 °C), solvent-to-sample ratio (20:1 mL g⁻¹), and pulse duty cycle (0.55 s⁻¹). An efficient extraction was achieved within 5 min, resulting in an extract with 47.78 ± 1.24 mg GAE 100 g⁻¹ DW for the total phenolic compounds and high antioxidant activity (87.28 ± 1.01% DPPH). Extraction by ultrasound was then concluded to facilitate a fast extraction rate with high reproducibility (coefficients of variation were less than 3% in the levels of antioxidant activity and phenolic compounds). Full article

(This article belongs to the Special Issue Agricultural Valorization of Agro-Industrial By-Products: From Waste to Value)

► Show Figures

Figure 1

12 pages, 887 KiB

Open AccessEditor’s ChoiceArticle

Agronomic Efficiency of Phosphorus Fertilisers Recovered from Milk Processing Waste

by Shane McIntosh, Terry Rose, Andrew Rose, Lee Kearney and Dirk Erler

Agronomy 2022, 12(10), 2341; https://doi.org/10.3390/agronomy12102341 - 28 Sep 2022

Cited by 2 | Viewed by 1628

Abstract

The recovery of phosphorus (P) from milk processing flotation sludges (MFS) using pyrolysis can contribute to a sustainable reuse of P by converting waste to fertiliser. The objectives of this study were to quantify the recovery and transformation of P following MFS pyrolysis and compare the efficacy of raw and pyrolysed MFS as organic P fertilisers. Phosphorus retention in biochars was high (98 ± 0.73% yield), leading to the enrichment of P relative to the raw MFS by a factor of 4.3–4.5. Pyrolysis of the MFS at 450 °C led to a 3-fold increase in the proportion of P in the HCl-extractable fraction (65 ± 0.32%), a 2-fold reduction in NaOH-P (30 ± 2.1%), and negligible amounts of P in the H₂O-P and NaHCO₃-P fractions. The bioavailability of P in raw MFS and 450 °C biochar was compared to a soluble P fertiliser in P-limiting plant bioassays. In the short-term (70 day) trial where ryegrass was grown on three soil types (Arenosol, Vertisol or Ferralsol), biochar MFS showed higher efficacy as a P fertiliser than raw MFS in the acidic Ferralsol, whereas the opposite response was observed in the near-neutral Arenosol. In the Vertisol, neither the raw MFS nor biochar produced more cumulative biomass or P uptake than any of the nil P controls. Over a longer 200-day period, raw MFS and biochar applied to the Arenosol were about 20% as efficient at providing P to ryegrass plants as the water-soluble K₂PO₄, suggesting that higher application rates of MFS or biochar would be required to match synthetic fertilisers in the short term. Full article

(This article belongs to the Special Issue Agricultural Valorization of Agro-Industrial By-Products: From Waste to Value)

► Show Figures

Graphical abstract

Review

Jump to: Research

20 pages, 351 KiB

Open AccessReview

Recovery of Energy and Nutrients from Mycotoxin-Contaminated Food Products through Biological Treatments in a Circular Economy Perspective: A Review

by Mirko Cucina and Chiara Tacconi

Agronomy 2022, 12(12), 3198; https://doi.org/10.3390/agronomy12123198 - 16 Dec 2022

Viewed by 1816

Abstract

Mycotoxins’ contamination of food products is a well-known issue that is gaining interest nowadays due to increasing contaminations that are also related to climate change. In this context, and considering the principles of Circular Economy, finding robust and reliable strategies for the decontamination and valorisation of mycotoxin-contaminated products becomes mandatory. Anaerobic digestion (AD) and composting appear as promising biological treatments to degrade mycotoxins and allow for recovering energy (i.e., biogas production) and materials (i.e., nutrients from digestate and/or compost). The aim of the present paper was to carry out an organic revision of the state of the art of energy and materials recovery from mycotoxin-contaminated food products through biological treatments, highlighting results and research gaps. Both processes considered were not generally affected by the contamination of the feedstocks, proving that these compounds do not affect process stability. Mycotoxins were highly removed due to the concurrence of microbiological and physical agents in AD and composting. From the literature review, emerged the points that still need to be addressed before considering large scale application of these processes, which are (i) to deepen the knowledge of biochemical transformations of mycotoxins during the processes, (ii) to assess the fate of mycotoxins’ residues and metabolites in soil once digestate/compost are applied, (iii) to evaluate and optimize the integration of AD and composting in order to increase the environmental and economical sustainability of the processes, and (iv) to update legislation and regulations to allow the agricultural reuse of organic fertilizers obtained from contaminated feedstocks. Full article

(This article belongs to the Special Issue Agricultural Valorization of Agro-Industrial By-Products: From Waste to Value)

► Show Figures

Journal Menu

Journal Browser

Agricultural Valorization of Agro-Industrial By-Products: From Waste to Value

Share This Special Issue

Special Issue Editors

Special Issue Information

Keywords

Benefits of Publishing in a Special Issue

Published Papers (13 papers)

Research

Review

Further Information

Guidelines

MDPI Initiatives

Follow MDPI