Genome sequence and gene expression studies reveal novel hydrogenases mediated hydrogen production by Clostridium biohydrogenum sp. nov., MCM B-509T

The present study describes Clostridium biohydrogenum sp. nov., MCM B-509T as one of the most efficient hydrogen producing dark fermentative bacteria. MCM B-509 produced 3.35 mol hydrogen per mole of glucose consumed. The draft genome sequence of MCM B-509 provided insights into gene repertoire involved in hydrogen metabolism. Genome analysis revealed the presence of key enzymes such as Fe hydrogenase, NiFe Hydrogenases, NAD dependent hydroxy-butyrate dehydrogenase and D-3 Phosphoglycerate dehydrogenase. Fe-hydrogenases were identified as novel hydrogenases on the basis of low sequence homology with the reference sequences in GenBank database as well as predicted 3D structure. Gene expression studies revealed genes encoding hydrogenases were upregulated and solventogenic pathway down regulated during exponential growth phase. Reverse was observed during stationary growth phase explaining high hydrogen production and decline during respective growth phases. This paper illustrates genetic investigation to explain high hydrogen production potential of C. biohydrogenum sp. nov., MCM B-509T.