The biotransformation of brewer’s spent grain into biogas by anaerobic microbial communities

In this study, we will show an effective conversion of BSG into biogas by selected microbial communities, obtained from different sources (animal manure and previously isolated microbial consortia). The stimulation of methanogenesis was reached by the co-digestion of JA’s phytomass (stem and leaves). The optimized conditions for microbial stable cultivation included the use of nutrient medium, containing yeast extract and trace element solution. The optimal BSG concentration in biogas production was 50 and 100 g L−1. Under thermophilic conditions, the maximum total methane production reached 64 %, and it comprised around 6–8 and 9–11 of L CH4 per 100 g of fermented BSG without and with co-digested JA, respectively, when the fresh inoculum was added. Although, after a year of re-cultivation, the values reduced to around 6–7, and 6–10 L CH4/100 g BSG, correspondingly, the selected microbial communities showed effective biotransformation of BSG. The supplementation of soil with the residual fermented BSG (10 %, w/w) resulted in the promotion of lettuce (Lepidium sativum L.) growth. The results obtained demonstrate a potential for complete BSG utilization via biogas production and application as a soil additive.

Source: World Journal of Microbiology and Biotechnology - October 27, 2015 Category: Microbiology Source Type: research