基因工程枯草杆菌生产中性蛋白酶的研究

Production of Neutral Protease by a Genetically Engineered Bacillus subtilis Strain

使用一株基因工程枯草杆菌ＤＢ４０３（ｐＷＬ２６７）生产中性蛋白酶，其宿主ＤＢ４０３失去了野生菌株９９％的胞外蛋白酶生产能力，质粒ｐＷＬ２６７则带有野生菌株中性蛋白酶的全部结构基因。在分批培养中，中性蛋白酶的活性为２６２ｍｇ／ｍｉｎ·Ｌ左右，通过培养基改进达到３．２８６ｇ／ｍｉｎ·Ｌ。连续培养表明，中性蛋白酶的比生产速率在比生长速率为０．２ｈ￣（－１）时最大。在控制补加葡萄糖和其它培养基成分的补料分批培养中，中性蛋白酶活性达１７．６７０ｇ／ｍｍ·Ｌ。

A genetically engineered Bacdillus subtilis strain, DB403(pWL267),was used to produce neutral protease. The host(DB403)loses 99%of the extracellular protease activity of the wild strain,while the plasmid (pWL267)contains whole structual gene of neutral protease. In batch cultivation, the activity of neutral protease was about 0. 262g/min·L. It increased to 3. 286g/min· L through the improvement of the medium. Continuous cultures were conducted and it showed that the maximum specific neutral protease productivity was obtained at the specif-ic growth rate around 0. 2h￣(-1). In fed batch culture,the activity of neutral protease was further increased to 17. 67 g/min L by controlling the feeding rates of glucose and other niedium components.