Cultural conditions of a thermostable Amylase of the obligate thermophile bacillus stearothermophile L-N 90

ABSTRACT

An obligate thermophile, Bacillus stearothermophilus, L.N. 90, produces remarkable amounts of a thermostable extracellular amylase in a nutrient yeast extract starch liquid medium at 55C with 48 h. Under static conditions. The effects exerted by adding 6 inorganic nitrogen sources, peptone, casein and urea, 17 amino acids 9 water, soluble vitamins, yeast-extract. Different buffers at various pH values, agitation speed and incubation time on amylase production were investigated. The most stimulatory factors were Tris-HCI [pH 7.6], peptone, vitamins, yeast extract and amino acids [cystine, valine, cysteine], whereas both aeration and agitation at different incubation periods exerted obvious inhibitory effects