Functional versus phylogenetic fingerprint analyses for monitoring hydrogen-producing bacterial populations in dark fermentation cultures

摘要

The fermentative hydrogen production occurs during the anaerobic digestion of organic matter. It is a promising technology to produce renewable energy. However, the mixed culture fermentation performances vary considerably depending on the operating conditions such as pH. We investigated the potential of a molecular CE-SSCP (capillary electrophoresis-single strand conformation polymorphism) fingerprinting method based on the hydA functional genes to better describe the bacterial community dynamics, with regards to the standard 16S rDNA-based method. A series of batch experiments was performed from sucrose at different initial pH from 4 to 6. As expected, the highest H_2 production potentials (H_(max)) and rates (R_(max)) were obtained at the highest pH. Changes in batch performances were clearly associated with shifts in the hydA diversity and structure. In contrast, 16S rDNA-based fingerprints were less sensitive to changes in H_2 production performances. The H_(max) was related to lower hydA diversity, with Clostridium sporogenes as the major H_2 producer. Communities harboring larger hydA diversities were found in experiments with the higher R_(max), suggesting that species coexistence may have positive effects on H_2 production.