The increasing global population and evolving dietary preferences demand sustainable and innovative food solutions. Edible filamentous fungi offer a promising protein source and are emerging as key ingredients in meat alternatives. This study investigates the quality and safety of Neurospora intermedia biomass (NIB), produced in a demo-scale bubble column reactor using grape marc (GM) and wine lees (WL) as cultivation media, and synthetic glucose medium (SYN) as a control. For submerged fermentation, GM and WL were used at 4% w/v and 50% v/v, respectively, whereas 1.5% w/v glucose was used for SYN. The NIB exhibited a complete amino acid profile, with notable levels of lysine (9.25-9.46%) and leucine (8.69-9.04%), and its lipid fraction was rich in unsaturated fatty acids-oleic (41.0-59.8%) and linoleic (19.7-33.9%), along with phosphorus (1097-2747 mg/100 g) and polyphenols (5.48-7.89 mg GAE/g). Overall, the proteomic analysis allowed the identification of more than 3000 proteins. Bioinformatic predictions identified potential allergens, which together accounted for only a minor fraction of the total protein mass. This study underscores NIBs grown on GM and WL as a functional and nutritious ingredient that has a rich and diverse protein profile with potentially low allergenicity. Additionally, it offers an innovative strategy that adds economic value to oenological by-products, reduces environmental impact, and promotes a circular bioeconomy. 

The global demand for sustainable protein sources—driven by population growth, climate change, and increasing pressure on conventional agriculture—has intensified the search for innovative, eco-friendly production methods. Post-distillation wine lees (vinasse) remains a largely underutilized byproduct of the wine and distillery industries. For every liter of ethanol produced, approximately 9–14 liters of vinasse are generated, creating a pressing need to manage trillions of liters annually. Due to its composition—particularly its high polyphenolic content and chemical oxygen demand—vinasse poses significant environmental and public health risks if not properly treated. This study presents a novel bioconversion strategy to valorize vinasse by cultivating protein-rich fungal biomass through submerged fermentation, using edible Ascomycetes and Zygomycetes filamentous fungi. The proposed biorefinery approach not only mitigates waste management challenges but also offers a scalable and sustainable pathway for alternative protein production. By converting a problematic effluent into a valuable resource, this bioprocess contributes to the development of circular, climate-smart food.

Wastewater streams contain both contaminants and valuable resources, making advanced treatment technologies essential for sustainable resource recovery. Without effective treatment, wastewater discharge leads to eutrophication, hypoxia, and the accumulation of toxic pollutants, severely impacting aquatic ecosystems and public health. However, wastewater is also a reservoir of recoverable nutrients (nitrogen, phosphorus), organic matter, and high-quality water, which can be efficiently reclaimed through advanced membrane technologies. Membrane bioreactors (MBRs) represent a significant advancement in wastewater treatment, integrating biological processes with membrane filtration to achieve high-efficiency pollutant removal and resource recovery. Utilising microfiltration (MF) or ultrafiltration (UF), MBRs enhance biomass retention, improve effluent quality, and enable the recovery of nutrients and energy carriers. Despite these advantages, challenges such as membrane fouling, high energy demands, and limited membrane longevity necessitate continuous technological improvements. Recent advancements in MBR technology focus on hybrid configurations incorporating forward osmosis (FO), reverse osmosis (RO), and electrochemical processes to enhance resource recovery efficiency. Innovations in nanocomposite membranes, antifouling surface modifications, and biofilm-resistant coatings aim to extend membrane lifespan and reduce operational costs. Artificial intelligence (AI)-driven real-time monitoring is further optimising process efficiency and energy consumption. Additionally, the integration of bioelectrochemical systems (BES) with MBRs is being explored for simultaneous wastewater treatment and energy recovery. This chapter critically examines the latest advancements in MBR technology, highlighting their role in circular economy frameworks and their potential for large-scale application in sustainable wastewater resource recovery. 

Wastes are unceasingly generated in the world, and most of them can be recycled, reused, or recovered to promote a circular economy. Among waste treatment approaches, the anaerobic digestion (AD) process has been considered as an ideal process due to its ecological benefits (reduction of unpleasant odor, pathogens accumulation, or greenhouse gas emission), social and economic advantages, and energy saving. In addition to biogas production, this process can be used to produce various bioproducts, such as biopolymers, bioplastics, biomass, biofertilizers, and biolipids. Interestingly, the AD process residue or digestate is a nutrient-rich by-product that can be used as a biofertilizer for agronomical purposes to balance N-P cycle in the soils. Despite of numerous benefits of AD, less than 1 % of waste is treated by this process. This process has the potential to be integrated with other waste treatment approaches to increase waste treatment efficiency. Therefore, it is essential to focus on each advantage and clarify ambiguity in order to satisfy more countries for employing AD for waste treatment. In this review, various benefits of AD are evaluated; and its potential impacts on particularly agriculture are examined in detail. Additionally, potential biomass and wastes that can be used for anaerobic digestion worldwide are deliberated. Besides, a critical perspective has been developed on the economic, environmental, and social evaluation of the benefits of AD and, as a final point, focused on an integrated circular cascading approach. 

The food industry generates substantial keratin waste, particularly chicken feathers, which are rich in amino acids and essential nutrients. However, the insolubility of keratin presents a significant challenge to its conversion. Keratinase, an enzyme produced by certain fungi and bacteria, offers a promising solution by degrading feather keratin into amino acids and soluble proteins. Among these, bacterial keratinase is notable for its superior stability and activity, although its production remains constrained, necessitating continued research to identify efficient microbial strains. Keratin-derived hydrolyzates, recognized for their biological and immunological properties, have garnered significant research interest. This review examines the structural characteristics of chicken feather keratin, its resistance to conventional proteases, and advances in keratinase production and purification techniques. Additionally, the keratin degradation mechanism and the adoption of environmentally friendly technologies for managing feather waste are explored. Finally, the review highlights the potential applications of keratinase across diverse industries, including animal feed and cosmetics. 

Upcycling fruit waste into health-promoting ingredients is an urgent sustainability challenge. In this work, a microbial degradation is described that converts apple pectin into bioactive pectic oligosaccharides (POS) using Bacillus subtilis HA1, a strain isolated from traditional yogurt. HA1 is γ-hemolytic, lecithinase-negative, and free of nhe/hbl enterotoxin genes, yet endures acid/bile and adheres to intestinal cells, confirming its safety and probiotic aptitude. The bacterium cleaves pectin within 6 h of incubation, and under optimum conditions (50 °C, pH 6), the extracellular pectinase showed a maximum activity of ≈18 IU/mL. TLC, LC–ESI–MS, and FTIR verify the formation of low-methylated mono- to tri-galacturonic acids. Crude POS scavenge up to 90 % of DPPH radicals at 10 mg/mL, which is five-fold higher than untreated pectin. POS also act selectively against tumor cells: MCF-7 breast cancer viability drops to 17 %, while healthy L-929 and HUVEC cells remain ≥95 % viable. Flow cytometry and qRT-PCR confirm apoptosis via Bax up-regulation and galectin-3 suppression. Altogether, probiotic candidate strains belonging to the B. subtilis afford a safe, eco-friendly route to high-value POS with potent antioxidant and anticancer activities, opening avenues for functional foods, nutraceuticals, and sustainable pectin valorization. 

Volatile fatty acids (VFAs) are widely used across various industries, representing a significant global market. However, conventional petroleum-based VFAs production raises environmental concerns. Waste-derived VFAs offer a sustainable alternative, but the complexity of feed compositions poses significant challenges for efficient post-processing. This study analyzes the effects of operating conditions and coexisting compounds – ammonium/phosphorus-containing compounds and inorganic salts – on the performance of nanofiltration (NF) membranes for VFA recovery. It addresses a gap in the literature by providing a comprehensive analysis and theoretical insights into the combined effects of feed composition, membrane properties, and operating parameters on the semi-selective separation and concentration of VFAs from complex aqueous matrices. Three NF membranes with different molecular weight cut-offs and zeta potentials were tested under varying feed pH (5.5 and 9), applied pressure (10 bar, 20 bar, and 30 bar), and operating temperature (20 °C and 40 °C). Synthetic solutions simulating pretreated anaerobic digestion effluents were used in partial recirculation cross-flow NF experiments. Results demonstrate that ammonium/phosphorus-containing compounds reduced VFAs rejection by up to 10 %, while inorganic salts increased it by up to 15 %, both contributing to reduced permeate flux. The combined effects of membrane properties, feed composition, feed pH, and operating conditions impact the VFAs rejection mechanisms. At lower pH, size exclusion is the dominant mechanism, whereas at higher pH, electrostatic repulsion becomes more important, enhancing VFAs rejection but reducing permeate flux. Temperature and pressure had strong effects: higher pressure improved both solute rejection and flux, while higher temperature increased flux but reduced solute rejection. Feed pH 9, pressure 30 bar, and temperature 40 °C were identified as the most suitable operating parameters for maximizing VFAs rejection, minimizing the rejection of coexisting compounds, and maximizing permeate flux. Under these conditions, a retentate containing about 29 g/L of VFAs was recovered. This study offers insights for optimizing NF processes to improve waste-derived VFAs valorization, advancing sustainable resource recovery and supporting the circular bioeconomy.

Erythromycin fermentation residue (EFR) is difficult to dispose of due to its high content of macrolide erythromycin. An alternative economic method was proposed in this study for erythromycin elimination in EFR through volatile fatty acid (VFA) production via an anaerobic digestion process. Different parameters were applied to evaluate the effects on energy recovery of VFA together with erythromycin elimination from EFR through batch assays under mesophilic conditions. Results demonstrated that anaerobic digestion technology for VFA production can significantly enhance erythromycin elimination in EFR. The highest removal efficiency of 86.7–87.5% was obtained at conditions of controlled pH at 11.0, with erythromycin decreasing from an initial 100.2 to 12.6–14.0 mg/L. Additionally, controlled pH during the digestion process was reported to positively improve VFA yield to a maximum of 1.04 g-COD/g-VS than the adjustment of initial pH (0.46 g-COD/g-VS). Metabolic analysis alongside high-throughput sequence analysis further demonstrated the high hydrolysis and acidogenesis activities of EFR during the VFA accumulation process. Dominate enzymes EC:3.2.1.40, EC:6.2.1.3, EC:4.1.2.14, EC:2.7.2.1, and EC:1.1.1.27 well balanced the whole process from organic to VFA at pH controlled 11.0. The current study provided a new feasible choice for the economical treatment of antibiotic fermentation residues due to the tolerable antibiotic removal efficiency and satisfactory VFA yield.

Investigation of the nutritional properties, biological activities, volatile compounds and sensory properties of fungal biomass and supernatants obtained from cheese whey powder fermented with Aspergillus oryzae and Neurospora intermedia was aimed in this study. The biomass produced by A. oryzae exhibited higher total lipid (118.54 g/kg) and total essential amino acid (62.05 g/kg) contents improve in comparison to N. intermedia. In contrast, the N. intermedia biomass showed superior bioactive properties, with the highest levels of total phenolics (4.72 mg gallic acid/g dry basis), total flavonoids, (23.85 mg quercetin/dry basis), and antioxidant activities (221.49 mg Trolox/g dry basis). Furthermore, the A. oryzae biomass derived from whey powder significantly enhanced the concentration of 1-octen-3-ol from 15.64 to 129.35 µg/kg, indicating its potential for improving the flavor profiles of food products with a natural mushroom-like aroma. Whey powder fermented with A. oryzae and N. intermedia contained significant amounts of calcium, sodium, and magnesium. The dominant mineral in the supernatant was Mg (7.40–7.90 mg/L) and a distinct fruity aroma was observed especially in the N. intermedia supernatant. These findings highlight the potential of fungal fermentation to convert dairy industry byproducts into nutrient-dense, flavor-enhancing alternatives.

The potential presence of toxic compounds in the digestate obtained from the anaerobic digestion of biodegradable waste restricts its application as a biofertilizer for soil conditioning and plant growth enhancement. The aim of this study was to assess digestate quality in terms of plant nutrient composition by evaluating the effects of activated carbon supplementation, inoculum source, and total solids content in the anaerobic digestion medium. The anaerobic digestion of food waste was conducted over a 60-day period at 25 °C in a 2.5 L bioreactor. The results demonstrated that inoculum diversity significantly impacted the digestate composition, particularly the zinc nutrient, with a p-value of 0.0054. This suggests that microbial diversity influences the valorization of organic waste into biofertilizer. However, the effects of inoculum diversity on other nutrients, aside from zinc, were not significant due to substantial interaction effects. Furthermore, assessing the impact of activated carbon supplementation proved challenging, as it was analyzed as part of a subset of the other two factors. The results of the digestate composition analysis indicated that activated carbon supplementation exhibited some influence on nutrient composition, necessitating further research to elucidate its significance. The findings of this study may contribute to enhancing the quality of digestate as a biofertilizer.