A dramatic increase in bio-hydrogen production has been achieved by a team of U.S. academic researchers. A Thermotoga maritima bacterium strain was successfully engineered to produce 46 percent more hydrogen per cell than naturally occurring forms of the microbe. The researchers exceeded the theoretical limit of 4 units of hydrogen for every unit of glucose fed the microbe by documenting a maximum yield of 5.7 units of hydrogen.Researchers engineered the bacterial species Thermotoga maritima to produce more hydrogen than any bacterium before it. Source: Scott Schrage, University of Nebraska-Lincoln

The bacterium ferments sugar into simpler carbon-based molecules that fuel new cell growth and produce metabolites, one of which is hydrogen. Most of that carbon is directed toward cell growth, diverting energy away from hydrogen production.

To stimulate hydrogen generation, the team temporarily inactivated a gene that slows hydrogen production, which induced a sugar-transporting gene to mutate to prevent sugar-based metabolite accumulation. The alteration also served to redirect microbial energy expenditure to hydrogen synthesis in a new strain labeled Tma 200.

Insertion of the mutated gene into a naturally occurring version of T. maritima resulted in overproduction of hydrogen similar to that observed for Tma 200.

The discovery by University of Nebraska-Lincoln, University of Connecticut and North Carolina State University researchers could support efforts to scale up the sustainable production of clean-burning hydrogen for vehicles and heavy industry.