VALORIZATION OF LIGNOCELLULOSIC BIOMASS BY DARK FERMENTATION: DEVELOPMENT OF EFFECTIVE CONDITIONS FOR MOLECULAR HYDROGEN BIOSYNTHESIS

Valorization of lignocellulosic biomass (LB) is important to reduce their environmental impact and reduce the risk to human health. Conventional methods for handling secondary raw materials primarily focus on waste disposal, treating lignocellulosic biomass as waste rather than as a source of organic substances for producing value-added products. As an alternative, processes should be developed to add value to waste, producing value-added products with economic and environmental benefits. In this regard, studies have focused on operating parameters, pretreatment, and microbial fermentation to enhance hydrogen yield during dark fermentation. Upper (4%) and lower (20%) concentrations of distillery grain based substrates for biohydrogen synthesis using wild-type E. coli have been established. Conditions for rational formation of reducing sugars by varying feedstock and acid concentrations in distillery grain based substrates have been established. During the study of the effect of acid-hydrothermal treatment of stillage on the total yield of biohydrogen, it was found that the optimal concentration of sulfuric acid is 1,5%, while 10% of the raw material is used. Under these conditions, the maximum yield of molecular hydrogen was achieved, equal to 116 ±1,0 ml/l using wild-type E. coli.