Today, food valorization represents an important challenge to environmental sustainability. Food waste can be used as a substrate for single cell protein production suitable for animal feed. In this study, animal and agricultural food waste, represented by fish, pineapple, banana, apple, and citrus peels, have been used simultaneously as a fermentation substrate for single cell protein production by Saccharomyces cerevisiae, to evaluate the possibility of using a multi complex substrate for a simultaneous biovalorization of different food waste. The fermentation process was implemented by the supplementation of a hydrolytic enzyme and nutrient to allow the best yeast growing conditions. At the end of the process, the final substrate was enriched in protein, reaching up to 40.19% of protein, making the multisubstrate useful for animal feed. The substrate was also investigated for crude lipid, ash, lignin, soluble and insoluble sugar. The substrate composition at the end of the fermentation process was represented by 14.46% of crude lipid, 1.08% ash, 6.29% lignin. Conversely, the soluble and insoluble sugars dropped down from 20.5% to 6.10% and 19.15% to 2.14%, respectively, at the end of the process.

Food contamination with microbial agents can take place at any stage of the food chain, from farm to fork. For this reason, good hygienic and manufacturing practices must be followed along the entire food chain to prevent microbiological food contamination due to microbes which can cause high incidence of morbidity and mortality among consumers. Recent research have been focused on the implementation of innovative technologies for enhancing the quality and safety of food without compromising its organoleptic and nutritional characteristics. Studies should be addressed to the development of simple, less expensive, and fast tests for monitoring and controlling microbial food contamination, as well as to the development of new food manufacturing processes.

Bioremediation stands as a promising solution amid the escalating challenges posed by environmental pollution. Over the past 25 years, the influx of synthetic chemicals and hazardous contaminants into ecosystems has required innovative approaches for mitigation and restoration. The resilience of these compounds stems from their non-natural existence, distressing both human and environmental health. Microbes take center stage in this scenario, demonstrating their ability of biodegradation to catalyze environmental remediation. Currently, the scientific community supports a straight connection between biorefinery and bioremediation concepts to encourage circular bio/economy practices. This review aimed to give a pre-overview of the state of the art regarding the main microorganisms employed in bioremediation processes and the different bioremediation approaches applied. Moreover, focus has been given to the implementation of bioremediation as a novel approach to agro-industrial waste management, highlighting how it is possible to reduce environmental pollution while still obtaining value-added products with commercial value, meeting the goals of a circular bioeconomy. The main drawbacks and challenges regarding the feasibility of bioremediation were also reported.

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.

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.

Agricultural food waste is rich in cellulosic and non-cellulosic fermentable substance. In this study, we investigated the bioconversion of pineapple waste cell wall sugars into bioethanol by simultaneous saccharification and fermentation using Saccharomyces cerevisiae ATCC 4126. Soluble and insoluble cell wall sugars were investigated during the fermentation process. Moreover, the fermentation medium was investigated for protein, moisture, ash, lignin and glycerol determinations with a particular focus on the increase in single cell protein due to yeast growth, allowing a total valorization of the resulting fermentation medium, with no further waste production, with respect to environmental sustainability. Soluble and insoluble sugars in the starting material were 32.12% and 26.33% respectively. The main insoluble sugars resulting from the cell wall hydrolysis detected at the beginning of the fermentation, were glucose, xylose and uronic acid. Glucose and mannose were the most prevalent sugars in the soluble sugars fraction. The ethanol theoretical yield, calculated according to dry matter lost, reached up to 85% (3.9% EtOH). The final fermentation substrate was mainly represented by pentose sugars. The protein content increased from 4.45% up to 20.1% during the process.