9] Culture of anaerobic bacteria for biochemical studies

Abstract

Publisher Summary This chapter discusses the general requirements for laboratory-scale culture of anaerobic microorganisms. Anaerobic bacteria specialized for the fermentation of a particular substrate frequently are isolated from soil or black mud by the enrichment culture technique, especially if strains having the desired properties are not already available in various collections as pure cultures. Alternatively, mutant strains of an available anaerobic organism can be isolated by suitable modification of the standard procedures used in the isolation of mutants of aerobic bacteria. When the microorganism to be cultivated requires a substrate readily fermented by many types of anaerobic bacteria, or complex sources of growth factors, such as yeast extracts, peptones, tryptones, and meat extracts, the medium should be sterilized prior to inoculation with the desired strain. The culture medium must be freed of dissolved oxygen prior to inoculation to culture the strictly anaerobic types of bacteria. Many of the anaerobic bacteria isolated from the soil grow optimally at room temperature or at 30° and may be cultivated successfully without elaborate incubator facilities. Even those with temperature optima in the range of 35° to 40° need not necessarily be cultivated at these higher temperatures. In some instances the rate of multiplication can be decreased by growth at a lower temperature to suit the time schedule of the investigator without any observable effect on the ultimate yield of a particular enzyme system.