Laboratoire de Genie Enzymatique et de Microbiologie, Ecole Nationale d'Ingenieurs de Sfax., Tunisia.
Can J Microbiol. 2009 Sep;55(9):1049-61. doi: 10.1139/w09-057.
A fibrinolytic enzyme producing bacterium was isolated and identified as Bacillus subtilis A26 on the basis of the 16S rRNA gene sequence. The fibrin zymography analysis reveals the presence of at least three fibrinolytic enzymes. The crude enzyme exhibited maximal activity at 60 degrees C and pH 8.0. Medium composition and culture conditions for the enzyme production by B. subtilis A26 were optimized using two statistical methods. The Plackett-Burman statistical design was applied to find the key ingredients and conditions for the best yield of enzyme production. Five significant variables (hulled grain of wheat, casein peptone, NaCl, CaCl2, and initial pH) were selected for the optimization studies. The response surface methodological approach was used to determine the optimal concentrations and conditions. The optimized medium contained 40.0 g.L-1 hulled grain of wheat, 3.53 g.L-1 casein peptone, 4.0 g.L-1 CaCl2, 3.99 g.L-1 NaCl, 0.01 g.L-1 MgSO4, and 0.01 g.L-1 KH2PO4, pH 7.78. The medium optimization resulted in a 4.2-fold increased level of fibrinolytic production (269.36 U.mL-1) compared with that obtained with the initial medium (63.45 U.mL-1). A successful and significant improvement in the production of protease by the A26 strain was accomplished using inexpensive carbon substrate (hulled grain of wheat), allowing a significant reduction in the cost of medium constituents.
从 16S rRNA 基因序列上，分离并鉴定出一种产生纤溶酶的细菌，命名为枯草芽孢杆菌 A26。纤维蛋白凝胶电泳分析显示至少存在三种纤溶酶。该粗酶在 60°C 和 pH8.0 时表现出最大活性。使用两种统计学方法优化了枯草芽孢杆菌 A26 产酶的培养基组成和培养条件。采用 Plackett-Burman 统计设计寻找最佳产酶产量的关键成分和条件。选择了 5 个显著变量（麦麸、酪蛋白胨、NaCl、CaCl2 和初始 pH）进行优化研究。响应面方法学方法用于确定最佳浓度和条件。优化后的培养基含有 40.0 g/L 麦麸、3.53 g/L 酪蛋白胨、4.0 g/L CaCl2、3.99 g/L NaCl、0.01 g/L MgSO4 和 0.01 g/L KH2PO4，pH 值为 7.78。与初始培养基（63.45 U/mL）相比，培养基优化使纤溶酶的产量提高了 4.2 倍（269.36 U/mL）。通过使用廉价的碳源（麦麸），成功地显著提高了 A26 菌株蛋白酶的产量，从而显著降低了培养基成分的成本。
