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A high load of inorganics in raw lignocellulosic biomass is known to inhibit the yield of bio-oil and alter the chemical reactions during fast pyrolysis of biomass. In this study, palm kernel shell (PKS), an agricultural residue from palm oil production, and two other woody biomass samples (mahogany (MAH) sawdust and iroko (IRO) sawdust) were pretreated with distilled water or an acidic solution (either acetic, formic, hydrochloric (HCl) or sulfuric acid (H2SO4)) before fast pyrolysis in order to investigate its effect on the primary products and pyrolysis reaction pathways. The raw and pretreated PKS, MAH and IRO were pyrolysed at 600 °C and 5 s with a micro-pyrolyser connected to a gas chromatograph–mass spectrometer/flame ionisation detector (GC-MS/FID). Of the leaching solutions, HCl was the most effective in removing inorganics from the biomass and enhancing the primary pyrolysis product formed compared to the organic acids (acetic and formic acid). The production of levoglucosan was greatly improved for all pretreated biomasses when compared to the original biomass but especially after HCl pretreatment. Additionally, the relative content of the saccharides was maximised after pretreatment with H2SO4, which was due to the increased production of levoglucosenone. The relative content of the saccharides increased by over 70%. This increase may have occurred due to a possible reaction catalysed by the remaining acid in the biomass. The production of furans, especially furfural, was increased for all pretreatments but most noticeable when H2SO4 was used. However, the relative content of acids and ketones was generally reduced for PKS, MAH and IRO across all leaching solutions. The relative content of the phenol-type compound decreased to a large extent during pyrolysis after acid pretreatment, which may be attributed to dehydration and demethoxylation reactions. This study shows that the production of valuable chemicals could be promoted by pretreatment with differ

Edible filamentous fungi, as a source of mycoprotein, is an emerging sustainable protein source as it can be cultivated on food-industry sidestreams, thus providing the food system with circularity. However, the digestibility of mycoprotein from different species of fungi is yet to be studied and compared to commonly consumed food proteins derived from muscle. Using the static INFOGEST in vitro gastrointestinal (GI) digestion protocol, but with less pancreatin than the recommended amount to omit high background from enzyme autolysis, this study investigated the protein degree of hydrolysis (DH%) and amino acid accessibility of five species of edible fungi in comparison with salmon fillet, chicken breast, beef tenderloin and casein. Three of the edible fungi species reached protein DH% between 58% ± 2.6% and 62% ± 5.6% during GI digestion compared to chicken, salmon, and beef reaching 62%–67% as well as casein at 55%. The amino acid accessibility of fungi (81%–92%), was comparable to that of salmon, chicken breast, and beef (90%–94%). This study thus indicated that edible fungi is a sustainable and nutritionally sound protein source.

Discovering eco-friendly alternatives to synthetic chemicals has become an increasingly popular area of research. Natural products are now in the spotlight for their potential use as replacements for synthetic chemicals. To maximize the benefits of these natural products, it is important to use efficient extraction methods, especially from agroindustrial waste. Olive oil mill wastewater (OOMW) is a byproduct of the olive oil production process and is considered a pollutant; however, OOMW contains a wide range of phenolic compounds that have proven antimicrobial properties. This study investigates the extraction of these compounds from OOMW, with the aim of determining their potential antimicrobial activities against several bacterial strains and fungi, including Bacillus spizizenii, Bacillus cereus, Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, Klebsiella aerogenes, Streptococcus uberis, Enterococcus faecalis, and Candida albicans. The OOMW extracts (OEs) were prepared by using three different solvents: ethyl acetate, ethanol, and methanol. The highest total phenolic contents (4.03 g, GAE/L) and the strongest antibacterial activity were obtained with methanol extraction. All OEs showed no antifungal activity against C. albicans. OEs, particularly methanol extracts of OOMW, can be used as bioactive substances in various industries as nutraceuticals and food ingredients, respectively.

Lignocellulosic materials are valuable resources in today's bioprocess technologies; however, their recalcitrance is a major barrier in industry regarding their conversion to microbial products. For this purpose, in this study, the synthesis of ionic liquids (ILs), its function in the hydrolysis of lignocellulosic materials, its biochemistry and possible toxic effects were investigated. In addition, the bioconversion of lignocellulosic materials pretreated with ionic liquids to biofuels (bioethanol, biobutanol, biogas and hydrogen) and various biochemicals is discussed in detail. For this, the focus is on the potential of ILs for industrial integration and use in large-scale reactors. ILs offer significant advantages due to their potential for ease of use and their features such as recovery and reuse after pretreatment. However, there are economic and technical problems that need to be solved to expand ILs in industrial systems and increase their use potential. To overcome these problems and the usability of ILs technologies in industry, techno-economic analyses has been examined and compared with traditional processes.

Various fruit and vegetable wastes, particularly peels, seeds, pulp, and unprocessed residues from the food industry, are abundant sources of antioxidants and essential antimicrobial agents. These valuable bioactive compounds recovered from the food industry have a great application in food, agriculture, medicine, and pharmacology. Food-derived natural antimicrobials offer advantages such as diminishing microbial loads and prolonging the shelf life of food products particularly prone to microbial spoilage. They not only enrich the foods with antioxidants but also help prevent microbial contamination, thereby prolonging their shelf life. Similarly, incorporating these natural antimicrobials into food packaging products extends the shelf life of meat products. Moreover, in agricultural practices, these natural antimicrobials act as eco-friendly pesticides, eliminating phytopathogenic microbes responsible for causing plant diseases. In medicine and pharmacology, they are being explored as potential therapeutic agents. This review article is based on current studies conducted in the last four years, evaluating the effectiveness of food-based natural antimicrobials in food, agriculture, medicine, and pharmacology., The article belongs to the Special Issue 10th Anniversary of Microorganisms: Past, Present and Future

The dairy industry generates excessive amounts of waste and by-products while it gives a wide range of dairy products. Alternative biotechnological uses of these wastes need to be determined to aerobic and anaerobic treatment systems due to their high chemical oxygen demand (COD) levels and rich nutrient (lactose, protein and fat) contents. This work presents a critical review on the fermentation-engineering aspects based on defining the effective use of dairy effluents in the production of various microbial products such as biofuel, enzyme, organic acid, polymer, biomass production, etc. In addition to microbial processes, techno-economic analyses to the integration of some microbial products into the biorefinery and feasibility of the related processes have been presented. Overall, the inclusion of dairy wastes into the designed microbial processes seems also promising for commercial approaches. Especially the digestion of dairy wastes with cow manure and/or different substrates will provide a positive net present value (NPV) and a payback period (PBP) less than 10 years to the plant in terms of biogas production.

In food industry, abundant fruit/vegetable byproducts (peel, seed, etc.) have been generated and released into the environment. These wastes can be considered as a largely available, low-cost source of value-added compounds. Among these, phenolic compounds are well-known for their beneficial effects on human health. Effective extraction methodologies are required for recovery of these phenolic compounds from agri-food wastes. These extracts can be used used as natural antimicrobials in pharmacology or disinfectants in food processing plants. In this work, pomegranate peel extracts were prepared by using different solvents to obtain high amount of phenolic-rich compounds. The pomegranate peel extracts were also tested against some important food pathogens to determine their antimicrobial and antibiofilm activities. Pomegranate peel extracts having high amount of phenolic compounds had higher antimicrobial and antibiofilm activities. As a result, phenolic-rich bioactive compounds can be recovered from food industry wastes and used as natural antimicrobial and antibiofilm agents. Thus, food industry wastes, especially fruit wastes, can be integrated into the extraction process and use in food, pharmacology, cosmetic and medicine industries.

BACKGROUND Vegetable oil is more difficult for microorganisms to degrade compared with carbohydrates and protein. Oil-rich waste creates serious environmental and health concerns if it remains untreated. The aim of the work reported here was to evaluate the effects on the nutritional composition of filamentous fungal biomass by growing it in pure olive oil as a carbon source. RESULTS The growth of different filamentous fungal strains (Aspergillus oryzae, Neurospora intermedia and Rhizopus oryzae) was investigated in pure olive oil. A pre-germination stage of either glucose or yeast extract was necessary for successful fungal growth in olive oil. A. oryzae showed superior performance in comparison with N. intermedia and R. oryzae in terms of biomass growth. The obtained biomass from A. oryzae and N. intermedia was analyzed for protein, fat, ash and alkali-insoluble material, where the presence of olive oil had a steering effect on biomass growth (16 g L−1 with oil versus 4 g L−1 without oil). Nutritional composition of the fungal biomass of A. oryzae contained 0.33% fat and 48% protein when cultivated in medium without olive oil supplementation, while 31% fat and 14% protein contents were observed in the presence of olive oil-containing medium. Similar trends for fat and protein contents were observed for the biomass of N. intermedia. Moreover, microscopy confirmed the presence of oil globules inside the fungal cells. CONCLUSIONS Fat composition of fungal biomass can be steered through addition of olive oil, which increases the versatility of the produced biomass for various applications, namely in feed, food and biofuel production.

Considering the projected demand for protein supplementation in animal feed, as well as prioritizing plant-based protein provision for the growing human population, great stress is imposed on conventional protein sources, calling for new sustainable alternatives. In this regard, the production and application of single-cell proteins (SCPs) has proven to be a promising alternative. Therefore, in this study, volatile fatty acids (VFAs) effluents recovered from anaerobically digested FW, CKM, CM, and their combinations were applied for the cultivation of edible filamentous fungi Aspergillus oryzae. The biomass was further evaluated considering its protein, fat and alkali insoluble material contents. The maximum fungal biomass yielded of 0.47 ± 0.00 and 0.37 ± 0.00 g dry biomass/g tVFAsCODeq.consumed, with up to 47% protein and 5% fat content successfully cultivated in shake flasks and bench scale reactors, respectively. In addition to the production of protein-rich biomass, significant reductions in medium COD (25–58%) and ammonium (33–48%) were achieved. The results presented in this research work imply that using waste-derived VFAs for the production of animal feed grade SCP is an innovative approach that can contribute to the economy and sustainability of animal feed production process. © 2021 by the authors. Licensee MDPI, Basel, Switzerland.

In this study, the antibacterial and antibiofilm properties of pomegranate (Punica granatum L.) extracts (PPLs) prepared by 10g of pomegranate peels (PPL10) and 100 mL of different solvents (ethanol, methanol, and their acid combinations, and water) were investigated as sources of bioactive compounds against food related bacteria. The antimicrobial activities of the extracts were measured by using agar well diffusion assay. The acid-treated extracts exhibited the highest antimicrobial activities (31-34 mm). The biofilm formations were assessed by using a microplate reader (570 nm) after crystal violet staining. The prevention and removal of bacterial biofilms were also evaluated by using extracts prepared by 5g of initial pomegranate peel (PPL5) with the different solvents or 200 ppm chlorine solution. All PPL5 and PPL10 extracts diluted at different ratios inhibited and removed biofilms and the highest antibiofilm effects were up to 80% by acid-treated extracts. In addition, PPL5s and PPL10s were as effective as or more effective than chlorine for the prevention of biofilms. Therefore, from an economical perspective the PPL5s could represent promising candidates as natural antibiofilm agents for food industry.

Fusarium species are the primary fungal pathogen affecting agricultural foodstuffs both in crop yield and economic loss. Due to these problems, control of phytopathogenic fungi has become one of the critical problems around the World. Nanotechnology is a new technology with potential in many fields, including agriculture. This study focused on determining potential effects of silver nanoparticles (AgNPs) with different nanosizes (3, 5, 8 and 10 nm) and at different concentrations (12.5–100 ppm) against phytopathogenic Fusarium oxysporum f. sp. radicis-lycopersici (FORL) strains. The maximum antifungal activity was achieved by decreasing nanosize and increasing concentration of AgNPs. Mycelium growth abilities were decreased about 50%, 75% and 90% by AgNPs treatment with 3 nm sizes at 25 ppm, 37.5 ppm and 50 ppm concentrations, respectively. The productivity of fungal biomass in the liquid growth media was found to be too limited at the 25–37.5 ppm of AgNPs concentrations with all sizes. In addition, both septation number and dimensions of micro- and macroconidia were found to be gradually decreased with the application of silver nanoparticles. This work showed that the low concentration of AgNPs could be used as potential antifungal agents and applied for control of phytopathogens.

Fish processing towards production of fillet gives rise to wastewater streams that are ultimately directed to biogas production and/or wastewater treatment. However, these wastewater streams are rich in minerals, fat, and proteins that can be converted to protein-rich feed ingredients through submerged cultivation of edible filamentous fungi. In this study, the origin of wastewater stream, initial pH, cultivation time, and extent of washing during sieving, were found to influence the amount of recovered material from the wastewater streams and its protein content, following cultivation with Aspergillus oryzae. Through cultivation of the filamentous fungus in sludge, 330 kg of material per ton of COD were recovered by sieving, corresponding to 121 kg protein per ton of COD, while through its cultivation in salt brine, 210 kg of material were recovered per ton of COD, corresponding to 128 kg protein per ton of COD. Removal ranges of 12–43%, 39–92%, and 32–66% for COD, total solids, and nitrogen, respectively, were obtained after A. oryzae growth and harvesting in the wastewater streams. Therefore, the present study shows the versatility that the integration of fungal cultivation provides to fish processing industries, and should be complemented by economic, environmental, and feeding studies, in order to reveal the most promising valorization strategy.

Olive oil mills represent an important sector in the Mediterranean Sea Basin but also an environmental hazard due to untreated wastewater. Recovery of nutrients from olive oil mill wastewater(OMWW)as protein-rich microbial biomass can produce novel feed and reduce its chemical oxygen demand; however, low-protein containing products have been reported. New strategies leading to higher protein-containing fungal biomass could renew the research interest on bioconversion for pollution mitigation of OMWW. In this work, through cultivation of edible filamentous fungi(Aspergillus oryzae, Neurospora intermedia, and Rhizopus delemar), a link between the protein content inthe originated fungal biomass, and the addition of nitrogen and medium dilution was established. Addition of nitrogen in the form of NaNO3 reduced the cultivation time from 96 h to 48 h while achieving a similar biomass mass concentration of 8.43 g/L and increased biomass protein content, from w = 15.9% to w = 29.5%. Nitrogen addition and dilution of OMWW, and consequent reduction of suspended solids, led to an increase in the protein content to up to w = 44.9%. To the best of our knowledge, the protein contents achieved are the highest reported to date and can open new research avenues towards bioconversion of OMWW using edible filamentous fungi.

The sidestreams produced during fish processing end in a separation tank where the resulting fractions follow biogas production or wastewater treatment. These streams can alternatively be used for production of protein-rich fungal biomass for e.g. fish feed applications, a product in increasing demand. These streams and upper streams originated during fish processing were used in this study for production of biomass using the edible filamentous fungus Rhizopus oryzae. The COD of the streams varied between 11 and 54 kg/m3 and, after fungal conversion of organic matter into protein-rich biomass and separation, a reduction of 34–69% was achieved. The stream origin had an effect on the final production and composition of the fungal biomass: 480 kg of biomass containing 33% protein per ton of COD were produced after cultivation in the separation tank streams, while 220 kg of biomass containing 62% protein per ton of COD were produced in upper sidestreams with lower amounts of suspended solids. Changing the initial pH (6.1–6.5) to 5.0 had a negative influence on the amount of biomass produced while medium supplementation had no influence. Thus, fish processing sidestreams can be diverted from biogas production and wastewater treatment to the production of protein-rich biomass for feed applications.

Ethanol production from whey powder was investigated by using free as well as alginate immobilized E. coli and E. coli expressing Vitreoscilla hemoglobin (VHb) in both shake flask and fermenter cultures. Media with varying levels of whey (lactose contents of 3%, 5%, 8% or 15%) and yeast extract (0.3% or 0.5%) were evaluated with fermentation times of 48–96 h. Immobilization and VHb expression resulted in higher ethanol production with all media; the increases ranged from 2% to 89% for immobilization and from 2% to 182% for VHb expression. It was determined that growth medium containing 8% lactose with 0.5% yeast extract yielded the highest ethanol production for free or immobilized strains, with or without VHb expression, in both shake flask and fermenter cultures. Immobilization with alginate was found to be a promising process for ethanol production by VHb-expressing ethanologenic E. coli.