Laboratoire de Génie Enzymatique et de Microbiologie, Ecole Nationale d'Ingénieurs de Sfax, B.P. 1173 Sfax, Tunisia.
J Ind Microbiol Biotechnol. 2010 Sep;37(9):983-90. doi: 10.1007/s10295-010-0792-8. Epub 2010 Aug 8.
This study is concerned with the co-production of alkaline proteases and thermostable alpha-amylase by some feather-degrading Bacillus strains: B. mojavensis A21, B. licheniformis NH1, B. subtilis A26, B. amyloliquefaciens An6 and B. pumilus A1. All strains produced both enzymes, except B. pumilus A1, which did not exhibit amylolytic activity. The best enzyme co-production was obtained by the NH1 strain when chicken feathers were used as nitrogen and carbon sources in the fermentation medium. The higher co-production of both enzymes by B. licheniformis NH1 strain was achieved in the presence of 7.5 g/l chicken feathers and 1 g/l yeast extract. Strong catabolic repression on protease and alpha-amylase production was observed with glucose. Addition of 0.5% glucose to the feather medium suppressed enzyme production by B. licheniformis NH1. The growth of B. licheniformis NH1 using chicken feathers as nitrogen and carbon sources resulted in its complete degradation after 24 h of incubation at 37 degrees C. However, maximum protease and amylase activities were attained after 30 h and 48 h, respectively. Proteolytic activity profiles of NH1 enzymatic preparation grown on chicken feather or casein-based medium are different. As far as we know, this is the first contribution towards the co-production of alpha-amylase and proteases using keratinous waste. Strain NH1 shows potential use for biotechnological processes involving keratin hydrolysis and industrial alpha-amylase and proteases co-production. Thus, the utilization of chicken feathers may result in a cost-effective process suitable for large-scale production.
本研究关注一些羽毛降解芽孢杆菌菌株（B. mojavensis A21、B. licheniformis NH1、B. subtilis A26、B. amyloliquefaciens An6 和 B. pumilus A1）同时生产碱性蛋白酶和热稳定α-淀粉酶的情况：除 B. pumilus A1 外，所有菌株均产生这两种酶，而 B. pumilus A1 则没有淀粉酶活性。当鸡羽毛作为发酵培养基中的氮源和碳源时，NH1 菌株获得了最佳的酶协同生产。在 7.5 g/l 鸡羽毛和 1 g/l 酵母提取物存在的情况下，B. licheniformis NH1 菌株同时生产这两种酶的能力更高。葡萄糖对蛋白酶和α-淀粉酶的产生有强烈的分解代谢抑制作用。向羽毛培养基中添加 0.5%葡萄糖可抑制 B. licheniformis NH1 的酶产生。B. licheniformis NH1 利用鸡羽毛作为氮源和碳源进行生长，在 37°C 孵育 24 小时后，其完全降解。然而，最大的蛋白酶和淀粉酶活性分别在 30 小时和 48 小时达到。NH1 酶制剂在鸡羽毛或酪蛋白基培养基上生长的蛋白水解活性谱是不同的。据我们所知，这是首次利用角蛋白废物同时生产α-淀粉酶和蛋白酶。NH1 菌株显示出在涉及角蛋白水解和工业α-淀粉酶和蛋白酶协同生产的生物技术过程中有潜在的用途。因此，鸡羽毛的利用可能会产生一种具有成本效益的适合大规模生产的工艺。
