Methane Production

Chapter 4 - Methane production

4.1 Microbial consortia and biological aspects of methane fermentation
4.2 Molecular biology of methanogens
4.3 Developments in bioreactor technology
References

Methane fermentation is a versatile biotechnology capable of converting almost all types of polymeric materials to methane and carbon dioxide under anaerobic conditions. This is achieved as a result of the consecutive biochemical breakdown of polymers to methane and carbon dioxide in an environment in which a variety of microorganisms which include fermentative microbes (acidogens); hydrogen-producing, acetate-forming microbes (acetogens); and methane-producing microbes (methanogens) harmoniously grow and produce reduced end-products. Anaerobes play important roles in establishing a stable environment at various stages of methane fermentation.
Methane fermentation offers an effective means of pollution reduction, superior to that achieved via conventional aerobic processes. Although practiced for decades, interest in anaerobic fermentation has only recently focused on its use in the economic recovery of fuel gas from industrial and agricultural surpluses.
The biochemistry and microbiology of the anaerobic breakdown of polymeric materials to methane and the roles of the various microorganisms involved, are discussed here. Recent progress in the molecular biology of methanogens is reviewed, new digesters are described and improvements in the operation of various types of bioreactors are also discussed.
4.1 Microbial consortia and biological aspects of methane fermentation

4.1.1 Hydrolysis and acidogenesis
4.1.2 Acetogenesis and dehydrogenation
4.1.3 Methanogenesis

Methane fermentation is the consequence of a series of metabolic interactions among various groups of microorganisms. A description of microorganisms involved in methane fermentation, based on an analysis of bacteria isolated from sewage sludge digesters and from the rumen of some animals, is

References: McCarty, P.L., In "Anaerobic Digestion 1981" Eds. Hughes, D.E. et.al., 3-22 (1982) Elsevier Biomedical Press, Amsterdam, New York, Oxford. Zeikus, J.G., Ann. Rev. Microbiol, 34, 423-464 (1980). Boone, D.R. et al., Appl. Environ. Microbiol., 40, 626-632 (1980). McInerney, M.J. et al., Appl. Environ. Microbiol., 41, 1029-1039 (1981). Thauer, R.K. et al., Bact. Rev., 41, 100-180 (1977). Hungate, R.E., Methods in Microbiol., 3B, 117-132 (1969). Wolfe, R.S., Trends in Biochem. Sci., 10, 396-399 (1985). Thauer, R.K. et.al., Ann. Rev. Microbiol., 43, 43-67 (1989). Leisinger, T. et.al., In "Genetics and Molecular Biology of Anaerobic Bacteria" Ed. Sebald, M., 1-12 (1993) Springer-Verlag, New York, Berlin, Heidelberg, London, Paris, Tokyo, Hong Kong, Barcelona, Budapest. Gernhardt, P. et.al., Mol. Gen. Genet., 221, 273-279 (1990). Sandbeck, K.A. et.al., Appl. Environ. Microbiol., 57, 2762-2763 (1991). Micheletti, P.A. et.al., J. Bacteriol, 173, 3414-3418 (1991). Lettinga, G. et.al., Biotech. Bioeng., 22, 699-734 (1980). Young, J.C. et.al., J. Wat. Poll. Contr. Fed., 41, 160-173 (1969). Jeris, J.S., Wat. Sci. Technol., 15, 167-187 (1983). Pohland, F.G. et.al., Environ. Lett., 1, 255-266 (1971). Bowker, R.P.G., Environ. Progress, 2, 235-242 (1983). Nagai, S. and Nishio, N., In "Handbook of Heat and Mass Transfer, vol. 3 Catalysis, Kinetics and Reactor Engineering" Ed. Cheremisinoff, N.P., 701-752 (1986) Gulf Publishing Corn., Houston, London, Paris, Tokyo. Kida, K. et al., In "Handbook of Heat and Mass Transfer, vol.3 Catalysis, Kinetics and Reactor Engineering" Ed. Cheremisinoff, N.P., 773-787 (1986) Gulf Publishing Corn., Houston, London, Paris, Tokyo. Palmer, J.R. and Reeve, J.N., In "Genetics and Molecular Biology of Anaerobic Bacteria" Ed. Sebald, M., 13-35 (1993) Springer-Verlag, New York, Berlin, Heidelberg, London, Paris, Tokyo, Hong Kong, Barcelona, Budapest.