The food industry consumes large amounts of water across various processes, and generates wastewater characterized by parameters like biochemical oxygen demand, chemical oxygen demand, pH, suspended solids, and nutrients. To meet environmental standards and enable reuse or valorization, treatment methods such as physicochemical, biological, and membrane-based processes are applied. This review focuses on the valorization of food industry wastewater in the biotechnological production of high-value products, with an emphasis on starch-rich wastewater, wineries and confectionery industry wastewater, and with a focus on new technologies for reduces environmental burden but also supports circular economy principles. Starch-rich wastewaters, particularly those generated by the potato processing industry, offer considerable potential for biotechnological valorization due to their high content of soluble starch, proteins, organic acids, minerals, and lipids. These effluents can be efficiently converted by various fungi (e.g., Aspergillus, Trichoderma) and yeasts (e.g., Rhodotorula, Candida) into value-added products such as lipids for biodiesel, organic acids, microbial proteins, carotenoids, and biofungicides. Similarly, winery wastewaters, characterized by elevated concentrations of sugars and polyphenols, have been successfully utilized as medium for microbial cultivation and product synthesis. Microorganisms belonging to the genera Aspergillus, Trichoderma, Chlorella, Klebsiella, and Xanthomonas have demonstrated the ability to transform these effluents into biofuels, microbial biomass, biopolymers, and proteins, contributing to sustainable bioprocess development. Additionally, wastewater from the confectionery industry, rich in sugars, proteins, and lipids, serves as a favorable fermentation medium for the production of xanthan gum, bioethanol, biopesticides, and bioplastics (e.g., PHA and PHB). Microorganisms of the genera Xanthomonas, Bacillus, Zymomonas, and Cupriavidus are commonly employed in these processes. Although there are still certain regulatory issues, research gaps, and the need for more detailed economic analysis and kinetics of such production, we can conclude that this type of biotechnological production on waste streams has great potential, contributing to environmental sustainability and advancing the principles of the circular economy.

In order to be competitive on the market, the production of biopreparations needs to be optimized, modeled and assessed in the early stages of its development. The aim of this paper was to optimize medium for the production of Trichoderma harzianum K179 biocontrol agent, to analyze its kinetics at enlarged laboratory scale and finally economic analysis of the production of this high-value product through simulation modelling. The results showed that the bioprocess of T. harzianum K179 bioagent production in a laboratory bioreactor on the medium with optimal composition (dextrose 10 g l⁻¹, soy flour 6.87 g l⁻¹, K₂HPO₄ 1.51 g l⁻¹, KCl 0.5 g l⁻¹ and MgSO₄ x 7H₂O 0.5 g l⁻¹), at stirring speed of 1.75 x g and aeration intensity of 1.5 vvm, can be shortened from 96 h to 36 h. The results of bioprocess economic analysis showed that with a 25-year project lifetime and investment payback time of 7.58 years, this project represents an economically viable system. Complete analysis of the bioprocess of Trichoderma harzianum K179 biocontrol agent production showed that the biologically produced preparation can be competitive on the market with synthetic preparations.

Background: Maize, one of the world’s most important food and feed crops, is often threatened by fungal infections that not only reduce yields but also contaminate grains with harmful mycotoxins. Methods: This study evaluated the biocontrol potential of Trichoderma harzianum K179 as an eco-friendly alternative to synthetic fungicides for protecting maize from two major pathogens, Fusarium graminearum and Aspergillus flavus. T. harzianum K179 was cultivated in a lab-scale bioreactor, and its antifungal activity was assessed through in vitro inhibition assays and two-year field trials. During the field trial, maize ear disease severity, yield, and mycotoxin levels in maize samples were monitored to assess the efficacy of the produced Trichoderma biopreparation. Results: In laboratory tests, T. harzianum K179 significantly inhibited both target pathogens. Field trials demonstrated that seed treatments with the Trichoderma bioagent reduced ear rot severity and increased grain yield compared to untreated and chemically treated controls. Notably, maize samples from T. harzianum-treated plots contained lower concentrations of key mycotoxins, including fumonisins and aflatoxins. Conclusions: These findings highlight the usefulness of T. harzianum K179 in integrated pest management strategies, offering a sustainable solution that enhances crop safety and productivity while mitigating the environmental risks associated with chemical fungicides.

Xanthan gum is one of the major commercial biopolymers employed in many industrial processes owing to its unique physical properties such as a high degree of pseudoplasticity and high viscosity even at low concentrations. Commercially available xanthan gum is relatively expensive due to glucose or sucrose being used as the sole carbon source for its production and cost reduction could be achieved by using less expensive substrates, such as food industrial wastewaters. Effluents from the confectionery industry, because of its high organic content, are significant environmental pollutants and before their release into environment it is necessary to purify them. The present study examines xanthan production by Xanthomonas campestris under aerobic conditions on wastewaters from five different factories of the confectionery industry. Xanthan yield was obtained as a quantitative characteristic of the process and was in the range between 4.28 g/L and 10.03 g/L and its quality is determined by following rheological characteristics of obtained cultivation media. The results obtained in this study indicate that wastewater from confectionary industry can be used as the basis of media for the production of this highly valuable product.

Search for more environment-friendly methods for controlling plant diseases that would contribute to the goal of sustainability in agriculture is in focus. In the present study, the potential of Streptomyces hygroscopicus isolated from soil sample in the production of biocontrol agents, nigericin and niphimycin, effective against Alternaria alternata storage apple pathogen was examined. Also, modelling and optimization of medium composition for biocontrol agent biosynthesis was performed. The results showed that the optimum amount of C₃H₈O₃, (NH₄)₂SO₄ and K₂HPO₄ in the medium for Streptomyces hygroscopicus biosynthesis is 20, 0.25 and 1.46 g/L, respectively. Scale-up and validation of the obtained results performed in the 3 L laboratory-scale bioreactor showed that on the optimized medium at an aeration rate of 0.7 vvm and an agitation speed of 200 rpm, produced nigericin and niphimycin, showed high activity. Under the same conditions, cultivation of S. hygroscopicus was performed in a 7 L laboratory bioreactor in a medium with waste glycerol instead of pure glycerol. Results showed that the methanol extract of S. hygroscopicus cultivation liquid, containing nigericin and niphimycin, was high effective against two Alternaria isolates. This was confirmed in vitro by obtaining large inhibition zone diameters on A. alternata KA10 (47 mm) and T1Jg₃ (44.33 mm) isolates. After successful in vitro analysis, in planta testing was performed. It was found that necrosis diameters that were measured on artificially inoculated apple fruits with A. alternata compared to necrosis diameter measured on untreated, control fruits, were 4.47 and 3.56 times smaller. GRAPHICAL ABSTRACT