Food Waste Valorization

A special issue of Fermentation (ISSN 2311-5637). This special issue belongs to the section "Industrial Fermentation".

Deadline for manuscript submissions: closed (31 August 2021) | Viewed by 65113

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Special Issue Editors

Department of Biomedical, Dental, Morphological and Functional Images Sciences, University of Messina, Messina, Italy
Interests: food contamination; food safety; plasticizers; bisphenols; environmental pollutants
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear Colleagues,

During the industrial processing of agricultural or animal products, large amounts of waste are produced. These wastes, generated in large amounts throughout the seasons of the year, can be considered the most abundant renewable resources on earth.

Due to the large availability and richness in components of these raw materials, there is a great interest in their reuse, both from an economical and environmental point of view.

This economical interest is based on the fact that a high quantity of such wastes could be used as low-cost raw materials for the production of new value-added compounds, with a further production cost reduction. The environmental concern is derived from their composition, especially the agro-industrial wastes that can contain potentially toxic compounds, which may cause deterioration of the environment when uncontrolled wastes are either burned, left on the soil to decay naturally or buried underground. Moreover, these materials exhibit both high biochemical oxygen demand (BOD) and chemical oxygen demand (COD) values, and give rise to serious pollution problems if not properly disposed of.

Recycling and transformation of food wastes represent a great opportunity in supporting a sustainable development by their conversion into value-added products, through the fermentation process.

The Special Issue will be focused on new food waste fermentation technologies and value-added products resulting from food waste fermentation. The main topics include, but are not limited to, the following:

- New fermentation processes;

- New food or feed production;

- SCP production;

- Biofuel production;

- Biomolecule production ;

- Upstream and downstream optimization;

- Fermentation product characterization.

Prof. Giuseppa Di Bella
Dr. Alessia Tropea
Guest Editors

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Keywords

  • fermentation process
  • food waste
  • value-added products
  • novel food
  • biofuel
  • SCP production
  • novel feed
  • microbial fermentation

Published Papers (17 papers)

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Editorial

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7 pages, 211 KiB  
Editorial
Food Waste Valorization
Fermentation 2022, 8(4), 168; https://doi.org/10.3390/fermentation8040168 - 06 Apr 2022
Cited by 15 | Viewed by 3691
Abstract
During the industrial processing of agricultural or animal products, large amounts of waste are produced. These wastes, generated in large amounts throughout the seasons of the year, can be considered the most abundant renewable resources on earth. Due to the large availability and [...] Read more.
During the industrial processing of agricultural or animal products, large amounts of waste are produced. These wastes, generated in large amounts throughout the seasons of the year, can be considered the most abundant renewable resources on earth. Due to the large availability and richness in components of these raw materials, there is a great interest in their reuse, both from an economical and environmental point of view. This economical interest is based on the fact that a high quantity of such wastes could be used as low-cost raw materials for the production of new value-added compounds, with a further production cost reduction. The environmental concern is derived from their composition, especially the agro-industrial wastes that can contain potentially toxic compounds, which may cause deterioration of the environment when uncontrolled wastes are either burned, left on the soil to decay naturally, or buried underground. Moreover, these materials exhibit both high biochemical oxygen demand (BOD) and chemical oxygen demand (COD) values and give rise to serious pollution problems if not properly discarded. Recycling and transformation of food wastes represent a great opportunity in supporting sustainable development by their conversion into value-added products through the fermentation process. Full article
(This article belongs to the Special Issue Food Waste Valorization)

Research

Jump to: Editorial, Review

14 pages, 425 KiB  
Article
Effect of Feeding Discarded Durian Peel Ensiled with Lactobacillus casei TH14 and Additives in Total Mixed Rations on Digestibility, Ruminal Fermentation, Methane Mitigation, and Nitrogen Balance of Thai Native–Anglo-Nubian Goats
Fermentation 2022, 8(2), 43; https://doi.org/10.3390/fermentation8020043 - 21 Jan 2022
Cited by 7 | Viewed by 2987
Abstract
The objective of this study was to evaluate the effect of fermented discarded durian peel with Lactobacillus casei TH14, cellulase, and molasses separately or in combination in total mixed rations on feed utilization, digestibility, ruminal fermentation, and nitrogen utilization in growing crossbreed Thai [...] Read more.
The objective of this study was to evaluate the effect of fermented discarded durian peel with Lactobacillus casei TH14, cellulase, and molasses separately or in combination in total mixed rations on feed utilization, digestibility, ruminal fermentation, and nitrogen utilization in growing crossbreed Thai Native–Anglo-Nubian goats. Five crossbreed Thai Native–Anglo-Nubian goats (50%) at 9 to 12 months of age and 20 ± 1 of body weight (BW) were assigned to a 5 × 5 Latin square design. Evaluated treatments were fermented discarded durian peel without additives (FDP), fermented discarded durian peel with 5% of molasses (FDPM), fermented discarded durian peel with 2% of cellulase (FDPC), fermented discarded durian peel with 1.0 × 105 cfu/g fresh matter of L. casei TH14 (FDPL), and fermented discarded durian peel with 5% of molasses and 1.0 × 105 cfu/g fresh matter of L. casei TH14 (FDPML). This study showed that acid detergent fiber intake was different (p < 0.05) between goats fed FDP and those fed FDPLM, 0.24 g/d and 0.20 g/d, respectively. The FDPML ration had significantly (p < 0.05) greater apparent nutrient digestibility and a better propionate concentration compared with other treatments. FDPML treatment significantly (p < 0.05) decreased the acetate-to-propionate ratio, methane production, and urinary nitrogen. Therefore, treated discarded durian peel with molasses and L. casei TH14 in combination could add 25% of dry matter into the diet for growing goats without a negative impact. Full article
(This article belongs to the Special Issue Food Waste Valorization)
9 pages, 851 KiB  
Article
Aspergillus oryzae Grown on Rice Hulls Used as an Additive for Pretreatment of Starch-Containing Wastewater from the Pulp and Paper Industry
Fermentation 2021, 7(4), 317; https://doi.org/10.3390/fermentation7040317 - 16 Dec 2021
Cited by 7 | Viewed by 2708
Abstract
From an industrial point of view, the use of microorganisms as a wastewater bioremediation practice represents a sustainable and economic alternative for conventional treatments. In this work, we investigated the starch bioremediation of paper mill wastewater (PMW) with Aspergillus oryzae. This amylase-producing [...] Read more.
From an industrial point of view, the use of microorganisms as a wastewater bioremediation practice represents a sustainable and economic alternative for conventional treatments. In this work, we investigated the starch bioremediation of paper mill wastewater (PMW) with Aspergillus oryzae. This amylase-producing fungus was tested in submerged fermentation technology (SmF) and solid-state fermentation (SSF) on rice hulls. The tests were conducted to assay the concentration of the reducing sugars on paper mill wastewater. The bioremediation of starch in the wastewater was carried out by A. oryzae, which proved capable of growing in this complex media as well as expressing its amylase activity. Full article
(This article belongs to the Special Issue Food Waste Valorization)
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16 pages, 3800 KiB  
Article
Green Husk of Walnuts (Juglans regia L.) from Southern Italy as a Valuable Source for the Recovery of Glucans and Pectins
Fermentation 2021, 7(4), 305; https://doi.org/10.3390/fermentation7040305 - 10 Dec 2021
Cited by 11 | Viewed by 3401
Abstract
Walnut green husk is an agricultural waste produced during the walnut (Juglans regia L.) harvest, that could be valued as a source of high-value compounds. In this respect, walnut green husks from two areas of Southern Italy (Montalto Uffugo and Zumpano), with [...] Read more.
Walnut green husk is an agricultural waste produced during the walnut (Juglans regia L.) harvest, that could be valued as a source of high-value compounds. In this respect, walnut green husks from two areas of Southern Italy (Montalto Uffugo and Zumpano), with different soil conditions, were investigated. Glucans and pectins were isolated from dry walnut husks by carrying out alkaline and acidic extractions, respectively, and then they were characterized by FT-IR, scanning electron microscopy (SEM) and differential scanning calorimetry (DSC). The colorimetric method for the enzymatic measurement of α- and β-glucans was performed. The maximum total glucan yield was recovered from Montalto walnut husks (4.6 ± 0.2 g/100 g DM) with a β-glucan percentage (6.3 ± 0.4) higher than that calculated for Zumpano walnut husks (3.6 ± 0.5). Thermal analysis (DSC) confirmed the higher degree of crystallinity of glucans from Zumpano. The pectin content for Montalto husks was found to be 2.6 times that of Zumpano husks, and the esterification degree was more than 65%. The results suggested that J. regia L. green husks could be a source of glucans and pectins, whose content and morphological and thermal characteristics were influenced by different soil and climate conditions. Full article
(This article belongs to the Special Issue Food Waste Valorization)
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11 pages, 988 KiB  
Article
Concentrated Buffalo Whey as Substrate for Probiotic Cultures and as Source of Bioactive Ingredients: A Local Circular Economy Approach towards Reuse of Wastewaters
Fermentation 2021, 7(4), 281; https://doi.org/10.3390/fermentation7040281 - 26 Nov 2021
Cited by 4 | Viewed by 2591
Abstract
Waste reduction and reuse is a crucial target of current research efforts. In this respect, the present study was focused on providing an example of local investment in a simple process configuration that converts whey into value-added compounds and allows recovery of a [...] Read more.
Waste reduction and reuse is a crucial target of current research efforts. In this respect, the present study was focused on providing an example of local investment in a simple process configuration that converts whey into value-added compounds and allows recovery of a clean water stream. In particular, buffalo milk whey obtained during mozzarella manufacturing was ultrafiltered in-house on spiral membrane modules (20 kDa), and the two obtained fractions, namely the retentate and the permeate, provided by the dairy factory, were further processed during this work. The use of an additional nanofiltration step allowed the recovery of high-quality water to be reused in the production cycle (machine rinsing water within the facility) and/or in agriculture, also reducing disposal costs and the environmental impact. The ultrafiltration retentate, on the other hand, was spray-dried and the powder obtained was used as the main substrate for the cultivation of Lactobacillus fermentum, a widely studied probiotic with anti-inflammatory, immunomodulatory and cholesterol-lowering properties. In addition, the same sample was tested in vitro on a human keratinocytes model. Resuspended concentrated whey powder improved cell reparation rate in scratch assays, assisted through time-lapse video-microscopy. Overall these data support the potential of buffalo whey as a source of biologically active components and recyclable water in the frame of a local circular economy approach. Full article
(This article belongs to the Special Issue Food Waste Valorization)
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10 pages, 610 KiB  
Article
Aquafeed Production from Fermented Fish Waste and Lemon Peel
Fermentation 2021, 7(4), 272; https://doi.org/10.3390/fermentation7040272 - 21 Nov 2021
Cited by 17 | Viewed by 3388
Abstract
In order to obtain a high-protein-content supplement for aquaculture feeds, rich in healthy microorganisms, in this study, Saccharomyces cerevisiae American Type Culture Collection (ATCC) 4126 and Lactobacillus reuteri ATCC 53608 strains were used as starters for fermenting fish waste supplemented with lemon peel [...] Read more.
In order to obtain a high-protein-content supplement for aquaculture feeds, rich in healthy microorganisms, in this study, Saccharomyces cerevisiae American Type Culture Collection (ATCC) 4126 and Lactobacillus reuteri ATCC 53608 strains were used as starters for fermenting fish waste supplemented with lemon peel as a prebiotic source and filler. Fermentation tests were carried out for 120 h until no further growth of the selected microorganisms was observed and the pH value became stable. All the samples were tested for proteins, crude lipids, and ash determination, and submitted for fatty acid analysis. Moreover, microbiological analyses for coliform bacteria identification were carried out. At the end of the fermentation period, the substrate reached a concentration in protein and in crude lipids of 48.55 ± 1.15% and 15.25 ± 0.80%, respectively, representing adequate levels for the resulting aquafeed, whereas the ash percentage was 0.66 ± 0.03. The main fatty acids detected were palmitic, oleic, and linoleic acids. Saturated fatty acids concentration was not affected by the fermentation process, whereas monounsaturated and polyunsaturated ones showed an opposite trend, increasing and decreasing, respectively, during the process. Coliform bacteria were not detected in the media at the end of the fermentation, whereas the amount of S. cerevisiae and L. reuteri were around 1011 and 1012 cells per g, respectively. Full article
(This article belongs to the Special Issue Food Waste Valorization)
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11 pages, 1912 KiB  
Article
Production and Maturation of Soaps with Non-Edible Fermented Olive Oil and Comparison with Classic Olive Oil Soaps
Fermentation 2021, 7(4), 245; https://doi.org/10.3390/fermentation7040245 - 29 Oct 2021
Cited by 5 | Viewed by 2949
Abstract
The study reports the alternative use of non-edible fermented olives for the production of high-quality natural soaps with a fast production process, low environmental impact, and without preliminary treatments for the raw material. Damaged olives, not used as food, were fermented naturally and [...] Read more.
The study reports the alternative use of non-edible fermented olives for the production of high-quality natural soaps with a fast production process, low environmental impact, and without preliminary treatments for the raw material. Damaged olives, not used as food, were fermented naturally and the oil was extracted by mechanical extraction. The product obtained was not for human consumption due to its high acidity, but it had a low content of peroxides. The non-edible olive oil obtained and an extra virgin olive oil, produced from the same olive cultivar, were subjected to saponification with sodium hydroxide. The soaps were produced with complete (0% of non-neutralized fatty acids) and incomplete (5% of non-neutralized fatty acids) saponification; the amount of sodium hydroxide to be used was determined with the saponification index. The soaps were aged for six months by monitoring pH, color, and behavior in an aqueous solution. The results show that the olives’ fermentation improves and speeds up the soap production and maturation process since the oil obtained from fermented non-edible olives is more suitable for the saponification process than the oil obtained from non-fermented edible olives. Non-edible fermented olives can be used for obtaining natural and high-quality soaps, reusing drupes classified as food waste. Full article
(This article belongs to the Special Issue Food Waste Valorization)
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16 pages, 1528 KiB  
Article
Production of Omega-3 Fatty Acids from the Microalga Crypthecodinium cohnii by Utilizing Both Pentose and Hexose Sugars from Agricultural Residues
Fermentation 2021, 7(4), 219; https://doi.org/10.3390/fermentation7040219 - 08 Oct 2021
Cited by 12 | Viewed by 2299
Abstract
The core objective of this work was to take advantage of the unexploited wheat straw biomass, currently considered as a broadly available waste stream from the Greek agricultural sector, towards the integrated valorization of sugar streams for the microbial production of polyunsaturated omega-3 [...] Read more.
The core objective of this work was to take advantage of the unexploited wheat straw biomass, currently considered as a broadly available waste stream from the Greek agricultural sector, towards the integrated valorization of sugar streams for the microbial production of polyunsaturated omega-3 fatty acids (PUFAs). The OxiOrganosolv pretreatment process was applied using acetone and ethanol as organic solvents without any additional catalyst. The results proved that both cellulose-rich solid pulp and hemicellulosic oligosaccharides-rich aqueous liquid fraction after pretreatment can be efficiently hydrolyzed enzymatically, thus resulting in high yields of fermentable monosaccharides. The latter were supplied as carbon sources to the heterotrophic microalga Crypthecodinium cohnii for the production of PUFAs, more specifically docosahexaenoic acid (DHA). The solid fractions consisted mainly of hexose sugars and led to higher DHA productivity than their pentose-rich liquid counterparts, which can be attributed to the different carbon source and C/N ratio in the two streams. The best performance was obtained with the solid pulp pretreated with ethanol at 160 °C for 120 min and an O2 pressure of 16 bar. The total fatty acids content reached 70.3 wt% of dried cell biomass, of which 32.2% was DHA. The total DHA produced was 7.1 mg per g of untreated wheat straw biomass. Full article
(This article belongs to the Special Issue Food Waste Valorization)
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13 pages, 658 KiB  
Article
Application of a Biosurfactant Produced by Bacillus cereus UCP 1615 from Waste Frying Oil as an Emulsifier in a Cookie Formulation
Fermentation 2021, 7(3), 189; https://doi.org/10.3390/fermentation7030189 - 12 Sep 2021
Cited by 17 | Viewed by 2420
Abstract
Biosurfactants have attracted increasing interest from the food industry due to their emulsifying, foaming and solubilizing properties. However, the industrial use of microbial biosurfactants has been hampered by the high production costs related mainly to the use of expensive substrates. The search for [...] Read more.
Biosurfactants have attracted increasing interest from the food industry due to their emulsifying, foaming and solubilizing properties. However, the industrial use of microbial biosurfactants has been hampered by the high production costs related mainly to the use of expensive substrates. The search for low-cost alternative substrates is one of the strategies adopted to overcome this problem. In the present study, a biosurfactant produced by Bacillus cereus UCP1615 by fermentation in a medium supplemented with waste frying soybean oil as a low-cost substrate was evaluated as a bioemulsifier for the production of cookies. The biosurfactant was evaluated for its emulsifying capacity against different vegetable oils, antioxidant activity and toxicity, demonstrating favorable results for use in food. In particular, it showed satisfactory antioxidant activity at the tested concentrations and no cytotoxicity to the L929 (mouse fibroblast) and Vero (monkey kidney epithelial) cell lines using the MTT assay. The biosurfactant was then added at different concentrations (0.25%, 0.5% and 1%) to a standard cookie dough formulation to evaluate the physicochemical characteristics of the product. Cookies formulated with the biosurfactant exhibited similar energy and physical characteristics to those obtained with the standard formulation but with a lower moisture content. The biosurfactant also ensured a good preservation of the cookie texture after 45 days of storage. These results suggest that the biosurfactant has a potential application as a green emulsifier in accordance with the demands of the current market for biocompatible products. Full article
(This article belongs to the Special Issue Food Waste Valorization)
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14 pages, 1126 KiB  
Article
A Comprehensive Bioprocessing Approach to Foster Cheese Whey Valorization: On-Site β-Galactosidase Secretion for Lactose Hydrolysis and Sequential Bacterial Cellulose Production
Fermentation 2021, 7(3), 184; https://doi.org/10.3390/fermentation7030184 - 08 Sep 2021
Cited by 8 | Viewed by 2937
Abstract
Cheese whey (CW) constitutes a dairy industry by-product, with considerable polluting impact, related mostly with lactose. Numerous bioprocessing approaches have been suggested for lactose utilization, however, full exploitation is hindered by strain specificity for lactose consumption, entailing a confined range of end-products. Thus, [...] Read more.
Cheese whey (CW) constitutes a dairy industry by-product, with considerable polluting impact, related mostly with lactose. Numerous bioprocessing approaches have been suggested for lactose utilization, however, full exploitation is hindered by strain specificity for lactose consumption, entailing a confined range of end-products. Thus, we developed a CW valorization process generating high added-value products (crude enzymes, nutrient supplements, biopolymers). First, the ability of Aspergillus awamori to secrete β-galactosidase was studied under several conditions during solid-state fermentation (SSF). Maximum enzyme activity (148 U/g) was obtained at 70% initial moisture content after three days. Crude enzymatic extracts were further implemented to hydrolyze CW lactose, assessing the effect of hydrolysis time, temperature and initial enzymatic activity. Complete lactose hydrolysis was obtained after 36 h, using 15 U/mL initial enzymatic activity. Subsequently, submerged fermentations were performed with the produced hydrolysates as onset feedstocks to produce bacterial cellulose (5.6–7 g/L). Our findings indicate a novel approach to valorize CW via the production of crude enzymes and lactose hydrolysis, aiming to unfold the output potential of intermediate product formation and end-product applications. Likewise, this study generated a bio-based material to be further introduced in novel food formulations, elaborating and conforming with the basic pillars of circular economy. Full article
(This article belongs to the Special Issue Food Waste Valorization)
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12 pages, 1505 KiB  
Article
The Use of Life Cycle Assessment in the Support of the Development of Fungal Food Products from Surplus Bread
Fermentation 2021, 7(3), 173; https://doi.org/10.3390/fermentation7030173 - 30 Aug 2021
Cited by 11 | Viewed by 3210
Abstract
The use of food waste as feedstock in the manufacture of high-value products is a promising avenue to contribute to circular economy. Considering that the majority of environmental impacts of products are determined in the early phases of product development, it is crucial [...] Read more.
The use of food waste as feedstock in the manufacture of high-value products is a promising avenue to contribute to circular economy. Considering that the majority of environmental impacts of products are determined in the early phases of product development, it is crucial to integrate life cycle assessment during these phases. This study integrates environmental considerations in the development of solid-state fermentation based on the cultivation of N. intermedia for the production of a fungal food product using surplus bread as a substrate. The product can be sold as a ready-to-eat meal to reduce waste while generating additional income. Four inoculation scenarios were proposed, based on the use of bread, molasses, and glucose as substrate, and one scenario based on backslopping. The environmental performance was assessed, and the quality of the fungal product was evaluated in terms of morphology and protein content. The protein content of the fungal food product was similar in all scenarios, varying from 25% to 29%. The scenario based on backslopping showed the lowest environmental impacts while maintaining high protein content. The results show that the inoculum production and the solid-state fermentation are the two environmental hotspots and should be in focus when optimizing the process. Full article
(This article belongs to the Special Issue Food Waste Valorization)
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16 pages, 2969 KiB  
Article
Optimization of Yeast, Sugar and Nutrient Concentrations for High Ethanol Production Rate Using Industrial Sugar Beet Molasses and Response Surface Methodology
Fermentation 2021, 7(2), 86; https://doi.org/10.3390/fermentation7020086 - 31 May 2021
Cited by 18 | Viewed by 9248
Abstract
Among the various agro-industrial by-products, sugar beet molasses produced by sugar refineries appear as a potential feedstock for ethanol production through yeast fermentation. A response surface methodology (RSM) was developed to better understand the effect of three process parameters (concentration of nutrient, yeast [...] Read more.
Among the various agro-industrial by-products, sugar beet molasses produced by sugar refineries appear as a potential feedstock for ethanol production through yeast fermentation. A response surface methodology (RSM) was developed to better understand the effect of three process parameters (concentration of nutrient, yeast and initial sugar) on the ethanol productivity using diluted sugar beet molasses and Saccharomyces cerevisiae yeast. The first set of experiments performed at lab-scale indicated that the addition of 4 g/L of nutrient combined with a minimum of 0.2 g/L of yeast as well as a sugar concentration lower than 225 g/L was required to achieve high ethanol productivities (>15 g/L/d). The optimization allowed to considerably reduce the amount of yeast initially introduced in the fermentation substrate while still maximizing both ethanol productivity and yield process responses. Finally, scale-up assays were carried out in 7.5 and 100 L bioreactors using the optimal conditions: 150 g/L of initial sugar concentration, 0.27 g/L of yeast and 4 g/L of nutrient. Within 48 h of incubation, up to 65 g/L of ethanol were produced for both scales, corresponding to an average ethanol yield and sugar utilization rate of 82% and 85%, respectively. The results obtained in this study highlight the use of sugar beet molasses as a low-cost food residue for the sustainable production of bioethanol. Full article
(This article belongs to the Special Issue Food Waste Valorization)
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14 pages, 1772 KiB  
Article
Utilization of Whey for Red Pigment Production by Monascus purpureus in Submerged Fermentation
Fermentation 2021, 7(2), 75; https://doi.org/10.3390/fermentation7020075 - 10 May 2021
Cited by 18 | Viewed by 3472
Abstract
Various biotechnological approaches have been employed to convert food waste into value-added bioproducts through fermentation processes. Whey, a major waste generated by dairy industries, is considered an important environmental pollutant due to its massive production and high organic content. The purpose of this [...] Read more.
Various biotechnological approaches have been employed to convert food waste into value-added bioproducts through fermentation processes. Whey, a major waste generated by dairy industries, is considered an important environmental pollutant due to its massive production and high organic content. The purpose of this study is to investigate the effect of different fermentation parameters in simultaneous hydrolysis and fermentation (SHF) of whey for pigment production with Monascus purpureus. The submerged culture fermentation parameters optimized were type and pretreatment of whey, pH, inoculation ratio, substrate concentration and monosodium glutamate (MSG) concentration. Demineralized (DM), deproteinized (DP), and raw whey (W) powders were used as a substrate for pigment production by simultaneous hydrolysis and fermentation (SHF). The maximum red pigment production was obtained as 38.4 UA510 nm (absorbance units) at the optimized condition of SHF. Optimal conditions of SHF were 2% (v/v) inoculation ratio, 75 g/L of lactose as carbon source, 25 g/L of MSG as nitrogen source, and fermentation medium pH of 7.0. The specific growth rate of M. purpureus on whey and the maximum pigment production yield values were 0.023 h−1 and 4.55 UAd−1, respectively. This study is the first in the literature to show that DM whey is a sustainable substrate in the fermentation process of the M. purpureus red pigment. Full article
(This article belongs to the Special Issue Food Waste Valorization)
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12 pages, 2149 KiB  
Article
Valorization of Rice Husk for the Production of Porous Biochar Materials
Fermentation 2021, 7(2), 70; https://doi.org/10.3390/fermentation7020070 - 30 Apr 2021
Cited by 19 | Viewed by 3710
Abstract
Rice husk (RH) is one of the most important crop residues around the world, making its valorization an urgent and important topic in recent years. This work focused on the production of RH-based biochars at different pyrolysis temperatures from 400 to 900 °C [...] Read more.
Rice husk (RH) is one of the most important crop residues around the world, making its valorization an urgent and important topic in recent years. This work focused on the production of RH-based biochars at different pyrolysis temperatures from 400 to 900 °C and holding times from 0 to 90 min. Furthermore, the variations in the yields and pore properties of the resulting biochars were related to these process conditions. The results showed that the pore properties (i.e., BET surface area and porosity) of the resulting RH-based biochar were positively correlated with the ranges of pyrolysis temperature and holding time studied. The maximal pore properties with a BET surface area of around 280 m2/g and porosity of 0.316 can be obtained from the conditions at 900 °C for a holding time of 90 min. According to the data on the nitrogen (N2) adsorption–desorption isotherms and pore size distributions, both microporous and mesoporous structures exist in the resulting biochar. In addition, the EDS and FTIR analyses also supported the slight hydrophilicity on the surface of the RH-based biochar due to the oxygen/silica-containing functional groups. Based on the findings of this work, the RH-based biochar could be used as a material in environmental applications for water conservation, wastewater treatment and soil amendment. Full article
(This article belongs to the Special Issue Food Waste Valorization)
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9 pages, 494 KiB  
Article
Analysis of Promotion Policies for the Valorization of Food Waste from Industrial Sources in Taiwan
Fermentation 2021, 7(2), 51; https://doi.org/10.3390/fermentation7020051 - 05 Apr 2021
Cited by 8 | Viewed by 2459
Abstract
Growing concern about circular bioeconomy and sustainable development goals (SDGs) for the valorization of food waste has raised public awareness since 2015. Therefore, the present study focused on the promotion policies and regulatory measures for the valorization of mandatory recyclable food waste from [...] Read more.
Growing concern about circular bioeconomy and sustainable development goals (SDGs) for the valorization of food waste has raised public awareness since 2015. Therefore, the present study focused on the promotion policies and regulatory measures for the valorization of mandatory recyclable food waste from industrial sources in Taiwan, including the animal/plant production farms and food-processing plants. According to the official data on the annual statistics during the period of 2015–2019, it showed that the food waste from alcoholic beverage manufacturers (i.e., lees, dregs, or alcohol mash) and oyster farms (i.e., waste oyster shell) accounted for about half (about 250,000 metric ton) of industrial food waste generation in Taiwan. In order to effectively reduce the burdens on incinerators/landfills and their environmental impacts, the central governing agencies jointly promulgated some regulatory measures for promoting the production of biobased products from the industrial food waste valorization like animal feed, soil fertilizer, and bioenergy. These relevant acts include the Waste Management Act, the Fertilizer Management Act, the Feed Management Act, and the Renewable Energy Development Act. In addition, an official plan for building the food waste bioenergy plants at local governments via anaerobic digestion process, which was estimated to be completed by 2024, was addressed as a case study to discuss their environmental and economic benefits. Full article
(This article belongs to the Special Issue Food Waste Valorization)
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Review

Jump to: Editorial, Research

21 pages, 597 KiB  
Review
Strategies to Increase the Value of Pomaces with Fermentation
Fermentation 2021, 7(4), 299; https://doi.org/10.3390/fermentation7040299 - 08 Dec 2021
Cited by 9 | Viewed by 3477
Abstract
The generation of pomaces from juice and olive oil industries is a major environmental issue. This review aims to provide an overview of the strategies to increase the value of pomaces by fermentation/biotransformation and explore the different aspects reported in scientific studies. Fermentation [...] Read more.
The generation of pomaces from juice and olive oil industries is a major environmental issue. This review aims to provide an overview of the strategies to increase the value of pomaces by fermentation/biotransformation and explore the different aspects reported in scientific studies. Fermentation is an interesting solution to improve the value of pomaces (especially from grape, apple, and olive) and produce high-added value compounds. In terms of animal production, a shift in the fermentation process during silage production seems to happen (favoring ethanol production rather than lactic acid), but it can be controlled with starter cultures. The subsequent use of silage with pomace in animal production slightly reduces growth performance but improves animal health status. One of the potential applications in the industrial context is the production of enzymes (current challenges involve purification and scaling up the process) and organic acids. Other emerging applications are the production of odor-active compounds to improve the aroma of foods as well as the release of bound polyphenols and the synthesis of bioactive compounds for functional food production. Full article
(This article belongs to the Special Issue Food Waste Valorization)
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34 pages, 1161 KiB  
Review
Agricultural Waste and Wastewater as Feedstock for Bioelectricity Generation Using Microbial Fuel Cells: Recent Advances
Fermentation 2021, 7(3), 169; https://doi.org/10.3390/fermentation7030169 - 28 Aug 2021
Cited by 62 | Viewed by 7803
Abstract
In recent years, there has been a significant accumulation of waste in the environment, and it is expected that this accumulation may increase in the years to come. Waste disposal has massive effects on the environment and can cause serious environmental problems. Thus, [...] Read more.
In recent years, there has been a significant accumulation of waste in the environment, and it is expected that this accumulation may increase in the years to come. Waste disposal has massive effects on the environment and can cause serious environmental problems. Thus, the development of a waste treatment system is of major importance. Agro-industrial wastewater and waste residues are mainly rich in organic substances, lignocellulose, hemicellulose, lignin, and they have a relatively high amount of energy. As a result, an effective agro-waste treatment system has several benefits, including energy recovery and waste stabilization. To reduce the impact of the consumption of fossil energy sources on our planet, the exploitation of renewable sources has been relaunched. All over the world, efforts have been made to recover energy from agricultural waste, considering global energy security as the final goal. To attain this objective, several technologies and recovery methods have been developed in recent years. The microbial fuel cell (MFC) is one of them. This review describes the power generation using various types of agro-industrial wastewaters and agricultural residues utilizing MFC. It also highlights the techno-economics and lifecycle assessment of MFC, its commercialization, along with challenges. Full article
(This article belongs to the Special Issue Food Waste Valorization)
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