Microbiology and physiology of anaerobic fermentations of cellulose. Progress report
This project studies the biochemistry and physiology of four major groups (primary, secondary, ancillary and methane bacteria) of anaerobic bacteria, that are involved in the conversion of cellulose to methane or chemical feedstocks. The primary bacterium, Clostridium thermocellum, has a cellulolytic enzyme system capable of hydrolyzing crystalline cellulose and consists of polypeptide complexes attached to the substrate cellulose with the aid of a low molecular yellow affinity substance (YAS) produced by the bacterium in the presence of cellulose. Properties of the complexes and YAS are studied. Aspects of metabolism are being studied which appear to be relevant for the interactions on consortia and their bioenergetics, particularly related to hydrogen, formate, CO, and CO{sub 2}. The roles of metals in the activation of H{sub 2} are being investigated, and genes for the hydrogenases cloned and sequenced to established structural relationships among the hydrogenases. The goals are to understand the roles and regulation of hydrogenases in interspecies H{sub 2} transfer, H{sub 2} cycling and the generation of a proton gradient. The structures of the metal clusters and their role in the metabolism of formate will be investigated with the goal of understanding the function of formate in the total synthesis of acetate from CO{sub 2} and its role in the bioenergetics of these microorganisms. Additionally, the enzyme studies will be performed using thermophiles and also the isolation of some new pertinent species. The project will also include research on the mechanism of extreme thermophily (growth over 70{degrees}) in bacteria that grow over a temperature span of 40{degrees}C or more. These bacteria exhibit a biphasic growth response to temperature and preliminary evidence suggests that the phenomenon is due to the expression of a new set of enzymes. These initial observations will be extended employing techniques of molecular biology.
- Research Organization:
- Georgia Univ., Athens, GA (United States)
- Sponsoring Organization:
- USDOE, Washington, DC (United States)
- DOE Contract Number:
- FG09-86ER13614
- OSTI ID:
- 10194361
- Report Number(s):
- DOE/ER/13614-T1; ON: DE95002899; TRN: 94:010386
- Resource Relation:
- Other Information: PBD: [1994]
- Country of Publication:
- United States
- Language:
- English
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Microbiology and physiology of anaerobic fermentations of cellulose. Progress report