Liu Baihong, Zhang Juan, Gu Lei, Du Guocheng, Chen Jian, Liao Xiangru
Synergetic Innovation Center of Food Safety and Nutrition, 214122, Wuxi, China.
Appl Biochem Biotechnol. 2014 Jul;173(5):1222-35. doi: 10.1007/s12010-014-0925-z. Epub 2014 May 1.
To explore a better expression system for the production of keratinase, the keratinase gene from Bacillus licheniformis BBE11-1 was expressed in Escherichia coli, Bacillus subtilis, and Pichia pastoris. The corresponding recombinant keratinases were named ker E, ker B, and ker P, respectively. All recombinant keratinases had an optimal pH at 10 although the pH stability of ker E and ker P was higher than that of ker E. The optimal temperature and thermostability of ker P were enhanced compared with those of ker E and ker B. The recombinant keratinases were inhibited by Mn2+ but experienced little influence from other metal ions. Furthermore, all recombinant keratinases could retain almost 80 % activity after treatment with 1 M hydrogen peroxide for 5 h. Under optimized conditions in a 3-L fermenter, the maximum keratinase activities obtained from recombinant B. subtilis and P. pastoris were 3,010 and 1,050 U/mL, respectively. This maximum keratinase activity from B. subtilis is the highest activity ever reported for any bacterial strain. These results indicate that B. subtilis is the ideal host for keratinase production, with potential applications in textile processing and feed supplements.
为探索用于生产角蛋白酶的更好表达系统，将地衣芽孢杆菌BBE11-1的角蛋白酶基因在大肠杆菌、枯草芽孢杆菌和毕赤酵母中进行表达。相应的重组角蛋白酶分别命名为ker E、ker B和ker P。所有重组角蛋白酶的最适pH均为10，尽管ker E和ker P的pH稳定性高于ker B。与ker E和ker B相比，ker P的最适温度和热稳定性有所提高。重组角蛋白酶受到Mn2+的抑制，但受其他金属离子的影响较小。此外，用1 M过氧化氢处理5 h后，所有重组角蛋白酶几乎都能保留80%的活性。在3-L发酵罐的优化条件下，重组枯草芽孢杆菌和毕赤酵母获得的最大角蛋白酶活性分别为3010和1050 U/mL。枯草芽孢杆菌的这种最大角蛋白酶活性是有史以来报道的任何细菌菌株中最高的活性。这些结果表明，枯草芽孢杆菌是生产角蛋白酶的理想宿主，在纺织加工和饲料添加剂方面具有潜在应用。
