Production of xylanase by an alkaline-tolerant marine-derived Streptomyces viridochromogenes strain and improvement by ribosome engineering
Production of xylanase by an alkaline-tolerant marine-derived Streptomyces viridochromogenes strain and improvement by ribosome engineering
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DOI：
10.1007/s00253-012-4290-y
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发表时间：
2013-05-01
影响因子：
5
通讯作者：
Bai, Fengwu
中科院分区：
文献类型：
--
作者：
Liu, Zhuo;Zhao, Xinqing;Bai, Fengwu
木聚糖酶是降解木聚糖的复合酶，然而，在海洋环境中，新型木聚糖酶生产者仍有待开发。本研究从海洋沉积物中筛选到一株具有木聚糖酶活性的链霉菌M11。M11的16 SrDNA序列与Streptomyces viridochromogenes的同源性最高（99%）。M11产木聚糖酶的最适pH为6.0，最适温度为70 ℃。M11木聚糖酶活性在6.0-9.0的pH范围内和60 A ℃下60 min是稳定的。观察到木聚糖酶活性在高达5 M NaCl的存在下是稳定的。对M11菌株进行了抗生素抗性筛选，筛选出的抗生素中以链霉素的效果最好。从含10 μ g/ml链霉素的平板中分离的突变株M11-1（10）显示出比野生型菌株高14%的木聚糖酶活性。对基因rpsL（编码核糖体蛋白S12）的分析表明，来自M11-1（10）的rpsL含有K88 R突变。这是首次报道海洋来源的S。绿色产色菌可作为木聚糖酶产生菌，利用核糖体工程提高链霉菌木聚糖酶产量也首次得到成功证实。
Xylanase is the enzyme complex that is responsible for the degradation of xylan; however, novel xylanase producers remain to be explored in marine environment. In this study, a Streptomyces strain M11 which exhibited xylanase activity was isolated from marine sediment. The 16S rDNA sequence of M11 showed the highest identity (99 %) to that of Streptomyces viridochromogenes. The xylanase produced from M11 exhibited optimum activity at pH 6.0, and the optimum temperature was 70 A degrees C. M11 xylanase activity was stable in the pH range of 6.0-9.0 and at 60 A degrees C for 60 min. Xylanase activity was observed to be stable in the presence of up to 5 M NaCl. Antibiotic-resistant mutants of M11 were isolated, and among the various antibiotics tested, streptomycin showed the best effect on obtaining xylanase overproducer. Mutant M11-1(10) isolated from 10 mu g/ml streptomycin-containing plate showed 14 % higher xylanase activities than that of the wild-type strain. An analysis of gene rpsL (encoding ribosomal protein S12) showed that rpsL from M11-1(10) contains a K88R mutation. This is the first report to show that marine-derived S. viridochromogenes strain can be used as a xylanase producer, and utilization of ribosome engineering for the improvement of xylanase production in Streptomyces was also first successfully demonstrated.