The anaerobic utilization of glycerol 3-phosphate (G3P) as carbon source and fumarate as hydrogen acceptor by E. coli will be further investigated. The anaerobic G3P dehydrogenase-fumarate reductase complex will be purified and resolved into component units. The possibility of coupled phosphorylation during the transfer of hydrogen from G3P to fumarate will be explored. The means by which oxygen modulates the expression of the genes of the glycerol system in E. coli and Klebsiella aerogenes will be explored both at the biochemical and genetic level. The mechanism of transport of glycerol and G3P into bacterial cells will be studied further.