Growth of thermophilic bacteria in rapemeal-derived media

A clarified, soluble, protein-rich medium was developed from rapemeal by boiling with 0·1 mmol/1 NaOH. The medium contained 78% of the original meal protein and supported the growth of a range of thermophilic micro-organisms that included Bacillus, Streptomyces and fungi. Amino acid analysis of the medium showed a full range of amino acids, and that acidic ones such as glutamate predominated. Growth of a thermophilic Bacillus spp. (termed 1/15) in the medium was biphasic and significant amounts of extracellular protease were synthesized during the scond growth phase. Biphasic growth was probably due to preferential utilization of free amino acids during the first phase of growth followed by degradation of proteins during the second phase.