METABOLIC ENGINEERING OF RHODOBACTER SPHAEROIDES FOR SUSTAINABLE PHOTOSYNTHETIC HYDROGEN PRODUCTION

(WYO-439-09)

Hydrogen is an efficient, portable, clean and renewable energy resource. It can be produced from three biological processes using (i) green alga or cyanobacteria under specific photosynthetic conditions, (ii) fermentative bacteria under anaerobic conditions in the absence of light and (iii) purple non-sulfur bacteria under anaerobic photosynthetic conditions. An integrated system that combines all three H2-producing components has been proposed to maximize H2 production per light input. In this system, purple non-sulfur bacteria, such as Rhodobacter sphaeroides, use volatile fatty acids produced by the fermentative bacteria as preferred source of carbon and reducing power and generate large quantities of H2. In addition, purple non-sulfur bacteria detoxify water, which can then be reused to grow algae. The ultimate energy input in this integrated system is sunlight. However, waste water generated from human or animal waste, which is rich in organic material, can be added and used by both fermentative bacteria and purple non-sulfur bacteria. These bacteria are natural components of waste water treatment microbial communities. The long-term objective of the assembled multidisciplinary consortium is to optimize a sustainable integrated photosynthetic hydrogen production system conceptually developed by the Department of Energy for application in Wyoming and other arid locations. The team has complementary expertise applicable to various components of the integrated system including bioinformatics, microbial genetics, genomics, transcriptomics, biochemistry, computational modeling of gene regulation and metabolism, chemical and mechanical engineering. The goal of this project is to metabolically engineer highly efficient H2 producing and water detoxifying strain of R. sphaeroides.

USDA CRIS Project Information Link: 0217099