FACTORS AFFECTING THE (PRODUCTION OF EXTRACELLULAR NEUTRAL PROTEASE) BY STREPTOMYCES MICROFLAVUS

In order to produce neutral protease from Streptomyces microflavus, it was cultivated in basal medium containing soluble starch, potassium nitrate, dipotassium hydrogen phosphate, magnesium sulphate, sodium chloride, calcium carbonate and ferrous sulphate. Protease production increased with decreasing the ratio of culture broth to vessel volume 1:5 and shaking at 150 rpm. Protease production was low when pH was 9. The productivity of protease decreased sharply when the incubation temperature increased from 30 to 450C. The maximum yield of protease was obtained at the third day of incubation. Soluble starch and yeast extract were the best carbon and nitrogen sources, respectively. Supplementation with calcium carbonate enhanced protease production. In addition, the dipotassium hydrogen phosphate was the best phosphorous source. Para chloromercuribenzoic acid and phenyl methylsulfonylfloride had significant inhibitory effect on protease production

Production and optimization of α-amylase from thermo-halophilic bacteria isolated from different local marine environments

Abstract Background Amylases are among the most important enzymes which are of great significance for biotechnology and have almost completely replaced chemical hydrolysis of starch in the starch processing industry. The present study was concerned with the production and optimization of extracellular α-amylase from Bacillus sp. NRC22017. Results The effect of various fermentation conditions on α-amylase production through shake-flask culture was investigated. Bacterial strain produces α-amylase was isolated from water in Wadi El-Natron. Based on microbiological, biochemical tests, and 16S rRNA gene sequences, the isolate was identified as Bacillus sp. NRC22017 and was later used for further studies. Maximum yield of α-amylase is 15.15 ± 0.47 U/ml from Bacillus sp. NRC22017; this strain is characterized with high temperature and high salinity in cultivated culture, and achieved maximum yield of α-amylase at pH 6.0 with inoculum size of 500 μl at 45 °C and aerobically incubation period of 72 h. The optimum volume of the fermentation medium was found to be 20 ml in 100 ml Erlenmeyer flask; the best starch and meat extract plus peptone concentration that provided the highest enzyme production from Bacillus sp. NRC22017 were found to be 2% and 1.05% (w/v) respectively. Conclusion Enzyme production was higher after optimizing the production conditions as compared to the basal medium