Payne G F, DelaCruz N, Coppella S J
Department of Chemical and Biochemical Engineering, University of Maryland, Baltimore 21228.
Appl Microbiol Biotechnol. 1990 Jul;33(4):395-400. doi: 10.1007/BF00176653.
Protein-secreting procaryotic host organisms are currently being sought as alternatives to Escherichia coli for recombinant processing. In this study we examined how manipulation of the cultivation conditions can enhance heterologous protein production by Streptomyces lividans. The recombinant S. lividans used in this study expressed and excreted a Flavobacterium enzyme capable of hydrolyzing organophosphates. Initial shake-flask studies demonstrated that supplementing Luria-Bertani medium with moderate amounts of glucose (30 g/l), led to improved enzyme production. In fermentor studies with controlled pH, a further twofold increase in production was observed when glucose was fed continuously as compared to batch cultivation. This improved production in the glucose-fed culture may be related to a reduced accumulation of acids. Continuous feeding of both glucose and tryptone led to a further sixfold increase in production. In addition to enhancing production 25-fold, the efficiency of enzyme production and the specific activity of the excreted enzyme were also improved by glucose and tryptone feeding. These results demonstrate that in addition to genetic manipulations, optimization of cultivation conditions can lead to significant improvements in the production of heterologous proteins from Streptomyces.
目前正在寻找分泌蛋白质的原核宿主生物体，以替代大肠杆菌进行重组加工。在本研究中，我们研究了如何通过操纵培养条件来提高淡紫链霉菌产生异源蛋白质的能力。本研究中使用的重组淡紫链霉菌表达并分泌了一种能够水解有机磷酸盐的黄杆菌酶。最初的摇瓶研究表明，在Luria-Bertani培养基中添加适量的葡萄糖（30 g/l）可提高酶的产量。在pH值受控的发酵罐研究中，与分批培养相比，连续补料葡萄糖时产量进一步提高了两倍。葡萄糖补料培养中产量的提高可能与酸积累的减少有关。同时连续补料葡萄糖和胰蛋白胨可使产量进一步提高六倍。除了将产量提高25倍外，补料葡萄糖和胰蛋白胨还提高了酶的生产效率和分泌酶的比活性。这些结果表明，除了基因操作外，优化培养条件可显著提高淡紫链霉菌异源蛋白质的产量。
