Effect of inoculum composition on microbial community involved in anaerobic digestion of sugarcane bagasse.
Andressa Rezende PereiraNathália Vercelli de AssisAline Gomes de Oliveira ParanhosDiego Roberto Sousa LimaBruno Eduardo Lobo BaetaSérgio Francisco de AquinoSilvana de Queiroz SilvaPublished in: Environmental technology (2023)
In anaerobic digestion (AD), the choice of inoculum type seems to be relevant for methane production for complex substrates, such as lignocellulosic material. Previous work demonstrated that the addition of fresh manure and ruminal fluid to anaerobic sludge improved methane productivity and kinetics of AD of crude sugarcane bagasse (CSB). Considering that the improvement of methane production could be a result of a more adapted microbial community, the present study performed Next Generation Sequencing analysis to identify changes in the microbiome of anaerobic sludge inoculum, resulting from fresh manure and ruminal fluids addition. In comparison with AD performed only with anaerobic sludge inoculum (50:50, U), accumulated methane production was 15% higher with anaerobic sludge plus ruminal fluid inoculum (50:50, UR) and even higher (68%) with anaerobic sludge with fresh bovine manure inoculum (50:50, UFM), reaching the value of 143 NmL CH4. g VS -1 . On the other hand, Clostridium species were highly abundant in all inocula, playing an important role during hydrolysis and fermentation of CSB, as well as to detoxify potential inhibitors. Microbial composition revealed the occurrence of Pseudomonas and Anaerobaculum at UFM inoculum that seem to have contributed to the higher methane production rate, mainly due to their hydrolytic and fermentative ability on lignocellulosic substrates. On the other hand, the presence of Alcaligenes might have had a negative effect on methane production due its ability to perform methane oxidation.