Topraktan alkalen proteaz üreticisi Bacillus sp. CA15 izole edildi. 16S ribosomal RNA gen dizilimine gore bu mikroorganizmanin Bacillus cereus ile çok yakin akraba oldugu tespit edildi. Proteaz üretiminin artisini saglamak için, kültür kosulari; karbon ve azot kaynaklari, metal iyonlari, pH ve isinin etkisi açisindan optimize edildi. En yüksek proteaz üretimi, %1 yagsiz süt tozu, %1 çözünür nisasta ve %0.6 $MgSO _4.7H _2O$ varliginda, baslangiç pH'si 8.0 ve 35°C'de üretilen kültürlerden elde edildi. Bu besiyerinde üretilen hücrelerin, canli hücre sayisinin, mL'de 1.8x108'e vardigi duragan fazda en iyi enzim aktivitesine rastlandi. Inorganik azot kaynaklari varliginda proteaz seviyesinin oldukça düsük oldugu bulundu. Sükroz ve laktozun varliginda da proteaz üretiminin azaldigi tespit edildi. Bacillus sp. CA15 alkalen proteazinin Triton X-100, Tween 20 and SDS'ye karsi son derece dayanikli oldugu gözlemlendi. Enzim aktivitesinin PMSF varliginda inhibe olmasi bu enzimin bir serin proteaz oldugunu düsündürdü.
An alkaline protease producer Bacillus sp. strain CA15 was isolated from soil. The microorganism was found to be closely related to Bacillus cereus based on 16S ribosomal DNA sequencing. The culture conditions for higher protease production were optimized with respect to carbon and nitrogen sources, metal ions, pH and temperature. Maximum protease production was obtained in the medium supplemented with 1% skim milk, 1% starch and 0.6% $MgSO _4.7H _2O$, initial pH 8.0 at 35°C. The best enzyme production was obtained during the stationary phase in which the cell density reached to 1.8x108 cells/mL. The level of protease was found to be low in the presence of inorganic nitrogen sources. The protease production was diminished in the presence of sucrose and lactose. The extreme stability towards Triton X-100, Tween 20 and SDS was observed by Bacillus sp. CA15 alkaline protease. The enzyme activity was inhibited by PMSF suggested that presence of serine residues at the active sites.
