Fermentative Escherichia coli makes a substantial contribution to H2 production in coculture with phototrophic Rhodopseudomonas palustris.

Individual species within microbial communities can combine their attributes to produce services that benefit society, such as the transformation of renewable resources into valuable chemicals. Under defined genetic and environmental conditions, fermentative Escherichia coli and phototrophic Rhodopseudomonas palustris exchange essential carbon and nitrogen, respectively, to establish a mutualistic relationship. In this relationship, each species produces H2 biofuel as a byproduct of its metabolism.

Pantothenate auxotrophy in Zymomonas mobilis ZM4 is due to a lack of aspartate decarboxylase activity.

The bacterium Zymomonas mobilis naturally produces ethanol at near theoretical maximum yields, making it of interest for industrial ethanol production. Zymomonas mobilis requires the vitamin pantothenate for growth. Here we characterized the genetic basis for the Z.