嗜麦芽窄食单胞菌(Stenotrophomonas maltophilia)DHHJ分解角蛋白的生化机制初探

A primary study on the biochemical mechanism of degrading keratins by Stenotrophomonas maltophilia DHHJ

对嗜麦芽窄食单胞菌(Stenotrophomonas maltophilia)DHHJ降解角蛋白的生化机制进行初步研究。结果发现:该细菌与羽毛共培养24 h后,电镜下观察到细菌紧密地生长在羽枝上,96 h后羽毛完全降解;该菌所产角蛋白酶属于胞外酶,胞内二硫键还原酶可提高该胞外酶活性3倍左右。单独的角蛋白酶和二硫键还原酶在没有活的细菌存在下,都不能完全降解羽毛,这说明细菌附着在降解过程中起了重要的作用,也可能是由于细菌持续提供了一种还原剂破坏二硫键。此外,羽毛降解过程中,在细菌与羽毛共培养液中检测到亚硫酸盐,说明亚硫酸盐解可能对羽毛降解也起了一定的作用。

Keratinolytic Stenotrophomonas maltophilia DHHJ was used to study the mechanism of keratinolysis. Observations from scanning electron microscopy images revealed that bacterial cells grew closely adhered to barbules of feathers within 24h, completely degrading them within 96h. Further observations indicated that Stenotrophomonas maltophilia DHHJ strain produced an extracellular protease, and keratinolytic activity was increased three times by the addition of intracellular disulfide reductases. Without the live bacterial cells, keratinase and disulfide reductase failed to degrade the whole feather alone, which shows that bacterial adhesion played a key role during the degradation process. And the bacterial cells might also provide a continuous supply of reductant to break disulfide bridges. In addition, sulfite was detected in the extracellular broth during feather degradation, suggesting that sulfitolysis might have some effect on feather degradation by the bacterium.