Production and chemical studies of protease from Bacillus subtilis (SH-6) Egyptian strain.
Bacillus subtilis (SH-6) Egyptian strain, isolated from hides, gave the highest protease activity. Luxurious growth and protease production were obtained by the use of a medium containing 8% of potato starch, 0,1 M of ammonium phosphate as carbon and nitrogen sources. Results indicate that borate buffer exerted a deleterious effect on the protease production. Comparing citrate and phosphate buffers, it was found that citrate gave lower protease activity than phosphate. There is a positive response to higher concentrations of phosphate ions. From the above-mentioned medium protease was precipitated and purified. The dried preparation of the enzyme was tested for its chemical composition. It revealed the absence of residual carbohydrate. Tests for phosphorus, sulfur, ferric, zinc, manganese, magnesium, and calcium ions were positive. Amino acids present were: L-leucine, cysteine, Dl-alanine, L-arginine, L-tyrosine, L-aspargine, L-proline, glycine, Dl-valine, L-histidine, L-glutamic, L-lysine, L-aspartic, Dl-tryptophan, L-cystine, Dl-serine and Dl-phenylalanine. Quantitative analysis of the preparation was 0.52% of ash and 14% of nitrogen.