Effect of physical irradiation and chemical mutagen treatment on methane production by methanogenic bacteria

Biomethanation is one of the desirable options for obtaining clean fuel from abundant renewable biomass resources. Improvement of biomethane production may be achieved by using improved strains of microbes, particularly the terminal microbes – the methanogens. Attempts have been made to improve the efficiency of the methanogens isolated from local sources by subjecting the methanogens to mutagenic changes by physical (by irradiation, neutron bombardment) or chemical (by addition of chemicals like acridine orange, colchicine) means. The effects of the treated methanogens on biomethanation were studied. Irradiation or neutron bombardment mutagenesis was dose-dependent and time-dependent. High doses proved to be lethal but methanogens were found to be to some extent radiation resistant when subjected to irradiation at small doses for short duration (5–10 s). No or marginal improvement of methane production occurred for the two strains TDM and TRM. Improvement of methane production occurred from successive transfers of radiation treated strain SSM. Chemical mutagens invariably inhibited biomethanation and the inhibition was dose dependent.