Vinasse bio-valorization for enhancement of Pleurotus biomass productivity: chemical characterization and carbohydrate analysis

Vinasse is a by-product of the sugar and alcohol industry with high toxicity and crop fertilization capacity. The bioconversion of vinasse to high-value products could represent an opportunity to reduce operating costs and environmental footprints. In this study, exopolysaccharides (EPSs) and fungal biomass were produced by different species of the genus Pleurotus (Pleurotus sajor-caju CCB 020, Pleurotus florida, Pleurotus ostreatoroseus, Pleurotus flabellatus, Pleurotus sp. CCB 068, and Pleurotus spleurotus) in submerged culture supplemented with different vinasse medium formulations. The highest yield of EPSs (about 7 g/L) was observed in the P. florida strain and the highest biomass in Pleurotus sp. CCB 068 with 28.8 g/L, after 14 days of fermentation. Results revealed that 100% vinasse is a suitable medium to achieve increased protein-rich biomass, exopolysaccharide content and minerals accumulation in the fungal biomass. Sugars predominant in the exopolysaccharide matrix were glucose, galactose, and mannose. Furthermore, the treatment of vinasse with Pleurotus provided efficient removal of color (98.8%) and turbidity (99%). The biomass following vinasse treatment can then be utilized for animal feed and human food supplementation, thus adding economic value to vinasse production.