Metabolic flux and functional potential of microbial community in an acidogenic dynamic membrane bioreactor

Abstract

In this study, a laboratory-scale acidogenic dynamic membrane bioreactor (DMBR) was operated with or without alginate immobilization under various hydraulic retention times. The interactions between biofilm formation, metabolic flux and predicted functional genes were investigated in the DMBR. Regardless of the alginate immobilization, hydrogen yield was increased after biofilm was formed on a supporting material. Metabolic flux shifts from homoacetogenic to hydrogenic pathways along with biofilm formation was confirmed by flux balance analysis for metabolites. KEGG ortholog count prediction of functional genes from microbial consortia using bioinformatics package (PICRUSt). Predicted enzymes showed similar levels of functional gene expression regardless of the immobilization status. PICRUSt result showed strong evidence of the functional relationship among hydrogen production, biofilm formation, and metabolic pathway. Taken together, this study provides to estimate characteristics of biofilm formation changes and to better understand the microbial metabolism of DMBR.