Upcycling of Beer Industry Wastewater: Biosurfactant Production and Application in Brewery Effluent Treatment

Abstract

The beer processing industry generates large amounts of effluents rich in organic and inorganic material, and complex and expensive systems are commonly used for their treatment. Therefore, new alternatives capable of ensuring sustainable industrial growth through cost-effective solutions are being studied. In this context, biosurfactants stand out due to their ability to degrade and remove contaminants from the environment. Therefore, the objective of this study was to evaluate the potential treatment of effluents from the beer industry using biosurfactants produced from wastewater from the beer industry. The biosurfactants were obtained by submerged cultivation at 30°C for 48 h using the bacterium Corynebacterium aquaticum in a mineral medium added of carbon source. The characterization of the biosurfactants was performed in relation to surface tension, emulsifying activity (EA), pH, and ionic character. The analyses were performed at 0, 24, and 48 h. The efficiency of the effluent treatments was evaluated by characterization in duplicate, before, during and after the treatment, regarding the concentrations of biochemical oxygen demand (BOD), chemical oxygen demand (COD), and total solids (TS). The best biosurfactant results were obtained using C. aquaticum in a medium with 10% (v/v) of brewing industry wastewater (BIW) as a carbon source after 48 h of cultivation, reaching a surface tension of 35.1 ± 0.2 mN/m, EA of 40.9 ± 0.5%, and stability under extreme conditions of temperature (−20°C to 121°C), salt (1% to 10%), and pH (4 to 10). Thus, the biosurfactant was applied for 10 days in an aerated biological treatment system. Best results were observed in biosurfactant concentrations of 0.5 CMD (critical micellar dilution), reaching improvement of up to 55.9% for BOD, 23.8% for COD, and 50.6% for TS. Thus, the biosurfactant produced (10% BIW) shows potential as an accelerator in the brewing industry effluent (BIE) treatment process, without purification and sterilization of the biocompound. Therefore, brewery wastewater proved to be a sustainable and nutritional substrate to obtain biosurfactants.