Predictive functional profiling of microbial communities in fermentative hydrogen production system using PICRUSt

Abstract PICRUSt (phylogenetic investigation of communities by reconstruction of unobserved states) is based on 16S rRNA sequencing data, which can analyze the microbial functions in fermentation system. In this study, PICRUSt was adopted to figure out the direct evidence of functions of the microbial community in biohydrogen production system. PICRUSt analysis demonstrated that metabolic flux shifted from acid-producing pathway to hydrogen-producing pathway, and the hydrogen-consuming homoacetogenic pathway was eliminated by ionizing radiation pretreatment at 5 kGy. KEGG (Kyoto Encyclopedia of Genes and Genomes) based functional genes analysis showed enriched energy metabolism and diminished homoaceto gene, which enhanced the hydrogen production. However, the diminished carbohydrate metabolism indicated that the pretreatment reduced the activity of microbial consortia to degrade various substrates. This study suggested that PICRUSt is an effective approach to analyze the functional profiling of microbial community in fermentative hydrogen production system.