Biogas production by anaerobic co-digestion of sugarcane biorefinery byproducts : comparative analyses of performance and microbial community in novel single-and two-stage systems.

Abstract

Anaerobic co-digestion (AcD) of sugarcane biorefinery byproducts (hemicelluloses hydrolysate (HH), vinasse, yeast extract and sugarcane bagasse fly ashes was evaluated using new anaerobic reactors fed with organic loading rates (OLR) from 0.9 to 10.8 g COD L−1 d−1. The best results were obtained in a two-stage system when the OLR was 5.65 g COD L−1 d−1, leading to a total chemical oxygen demand (COD) removal of 87.6 % and methane yield of 243 NmL CH4 g CODr−1. Microbial community analyses of sludge from both systems (one and two-stages) revealed structural changes and relationship among the main genus found (Clostridium (62.8%), Bacteroides(11.3 %), Desulfovibrio (19.1 %), Lactobacillus(67.7 %), Lactococcus (22.5%), Longilinea (78%), Methanosaeta (19.2 %) and Syntrophus (18.9 %)) with processes performance, kinetic and hydrodynamic parameters. Moreover, biomass granulation was observed in the novel structured anaerobic reactor operated at single stage due to sugarcane bagasse fly ash addition.