Department of Biological and Geological Sciences, Faculty of Education, Ain Shams University, Roxy, 11435, Cairo, Egypt.
J Microbiol. 2012 Feb;50(1):103-11. doi: 10.1007/s12275-012-1343-y. Epub 2012 Feb 27.
Thirty bacterial strains were isolated from the rhizosphere of plants collected from Egypt and screened for production of chitinase enzymes. Bacillus thuringiensis NM101-19 and Bacillus licheniformis NM120-17 had the highest chitinolytic activities amongst those investigated. The production of chitinase by B. thuringiensis and B. licheniformis was optimized using colloidal chitin medium amended with 1.5% colloidal chitin, with casein as a nitrogen source, at 30°C after five days of incubation. An enhancement of chitinase production by the two species was observed by addition of sugar substances and dried fungal mats to the colloidal chitin media. The optimal conditions for chitinase activity by B. thuringiensis and B. licheniformis were at 40°C, pH 7.0 and pH 8.0, respectively. Na(+), Mg(2+), Cu(2+), and Ca(2+) caused enhancement of enzyme activities whereas they were markedly inhibited by Zn(2+), Hg(2+), and Ag(+). In vitro, B. thuringiensis and B. licheniformis chitinases had potential for cell wall lysis of many phytopathogenic fungi tested. The addition of B. thuringiensis chitinase was more effective than that of B. licheniformis in increasing the germination of soybean seeds infected with various phytopathogenic fungi.
从埃及采集的植物根际中分离出 30 株细菌菌株，并对其产生几丁质酶的能力进行了筛选。在研究的菌株中，苏云金芽孢杆菌 NM101-19 和地衣芽孢杆菌 NM120-17 的几丁质酶活性最高。苏云金芽孢杆菌和地衣芽孢杆菌的几丁质酶生产通过在胶体几丁质培养基中添加 1.5%胶体几丁质，并以干真菌垫和蛋白胨作为氮源，在 30°C 下孵育五天进行优化。在胶体几丁质培养基中添加糖物质和干真菌垫可观察到两种细菌的几丁质酶产量增加。苏云金芽孢杆菌和地衣芽孢杆菌几丁质酶的最佳条件分别为 40°C、pH7.0 和 pH8.0。Na(+)、Mg(2+)、Cu(2+)和 Ca(2+)可增强酶活性，而 Zn(2+)、Hg(2+)和 Ag(+)则显著抑制酶活性。在体外，苏云金芽孢杆菌和地衣芽孢杆菌的几丁质酶对多种植物病原真菌的细胞壁裂解具有潜在作用。添加苏云金芽孢杆菌几丁质酶比添加地衣芽孢杆菌几丁质酶更能提高感染各种植物病原真菌的大豆种子的发芽率。
