Unraveling Biohydrogen Production and Sugar Utilization Systems in the Electricigen Shewanella marisflavi BBL25

Identification of novel, electricity-producing bacteria has garnered remarkable interest because of the various applications of electricigens in microbial fuel cell and bioelectrochemical systems. Shewanella marisflavi BBL25, an electricity-generating microorganism, uses various carbon sources and shows broader sugar utilization than the better-known S. oneidensis MR-1. To determine the sugar-utilizing genes and electricity production and transfer system in S. marisflavi BBL25, we performed an in-depth analysis using whole-genome sequencing. We identified various genes associated with carbon source utilization and the electron transfer system, similar to those of S. oneidensis MR-1. In addition, we identified genes related to hydrogen production systems in S. marisflavi BBL25, which were different from those in S. oneidensis MR-1. When we cultured S. marisflavi BBL25 under anaerobic conditions, the strain produced 427.58 +/- 5.85 mu l of biohydrogen from pyruvate and 877.43 +/- 28.53 mu l from xylose. As S. oneidensis MR-1 could not utilize glucose well, we introduced the glk gene from S. marisflavi BBL25 into S. oneidensis MR-1, resulting in a 117.35% increase in growth and a 17.64% increase in glucose consumption. The results of S. marisflavi BBL25 genome sequencing aided in the understanding of sugar utilization, electron transfer systems, and hydrogen production systems in other Shewanella species.

Automated summary

This study identified genes associated with carbon source utilization, electron transfer systems, and hydrogen production systems in Shewanella marisflavi BBL25 through whole-genome sequencing. In addition, introducing the glk gene from S. marisflavi BBL25 into S. oneidensis MR-1 improved glucose consumption. The findings contribute to the understanding of sugar utilization, electron transfer systems, and hydrogen production systems in other Shewanella species.