Department of Chemical Sciences, University of Naples 'Federico II', Complesso Universitario Monte S. Angelo, Naples, Italy.
FEMS Microbiol Lett. 2013 Feb;339(2):93-101. doi: 10.1111/1574-6968.12057. Epub 2012 Dec 17.
Ninety bacteria isolated from raw composting materials were screened for their cellulolytic activity on solid medium containing carboxymethylcellulose. The bacteria producing the highest cellulolytic activity levels were identified by 16S rRNA sequencing as Bacillus licheniformis strain 1, Bacillus subtilis subsp. subtilis strain B7B, Bacillus subtilis subsp. spizizenii strain 6, and Bacillus amyloliquefaciens strain B31C. Cellulase activity production by the most productive strain B. amyloliquefaciens B31C was optimized in liquid culture varying the carbon source. Comparison of growth curves of B. amyloliquefaciens B31C at temperatures from 28 to 47 °C indicated its thermotolerant nature. Moreover, analysis of time courses of cellulase activity production in this thermal range showed that increase of temperature from 28 to 37 °C causes an increase of cellulase activity levels. Investigating the enzymes responsible for cellulase activity produced by B. amyloliquefaciens B31C by proteomic analyses, an endoglucanase was identified. It was shown that the purified enzyme catalyzes carboxymethylcellulose's hydrolysis following Michaelis-Menten kinetics with a K(M) of 9.95 mg ml(-1) and a v(max) of 284 μM min(-1) . It shows a retention of 90% of its activity for at least 144 h of incubation at 40 °C and exhibits a range of optimum temperatures from 50 to 70 °C.
从原始堆肥材料中分离出的 90 株细菌在含有羧甲基纤维素的固体培养基上进行了筛选，以检测其纤维素酶活性。通过 16S rRNA 测序鉴定出产生最高纤维素酶活性水平的细菌为地衣芽孢杆菌 1 株、枯草芽孢杆菌亚种枯草芽孢杆菌 B7B 株、解淀粉芽孢杆菌 6 株和解淀粉芽孢杆菌 B31C 株。最具生产力的菌株 B. amyloliquefaciens B31C 的纤维素酶活性生产在液体培养中通过改变碳源进行了优化。比较 B. amyloliquefaciens B31C 在 28 至 47°C 温度下的生长曲线表明其具有耐热性。此外，在该温度范围内分析纤维素酶活性产生的时间过程表明，温度从 28°C 升高到 37°C 会导致纤维素酶活性水平的增加。通过蛋白质组学分析研究了 B. amyloliquefaciens B31C 产生的纤维素酶活性的酶，鉴定出一种内切葡聚糖酶。结果表明，该纯化酶在米氏动力学下催化羧甲基纤维素的水解，K（M）为 9.95mg ml（-1），v（max）为 284μM min（-1）。它在 40°C 孵育至少 144 小时后保持 90%的活性，并且表现出 50 至 70°C 的最佳温度范围。
