纤维素降解菌CMC-4的分离鉴定、诱变和酶学特性研究

发布时间：2018-09-12 06:43

【摘要】：从秸秆还田土壤中初筛获得一株高效纤维素降解菌CMC-4,根据菌株形态、理化性质及16S rDNA序列分析,初步鉴定为地衣芽孢杆菌(Bacillus licheniformis)。以此为出发菌株,经亚硝酸钠诱变获得一株稳定高产纤维素酶突变株CMC-4-3。对CMC-4和CMC-4-3的产酶条件和酶学性质进行比较分析,结果表明:CMC-4-3纤维素酶活力较CMC-4提高67.5%;其最适产酶条件是:37℃、pH 6.0、葡萄糖为碳源、蛋白胨为氮源、接种量2.0%、装液量60 ml/250 ml。该菌株所产纤维素酶的最适反应pH为6.0,且在4.0~7.0酶活力较稳定;最适反应温度为50℃,在20~80℃范围内均保持稳定;金属离子Fe~(2+)、Mg~(2+)、Co~(2+)、K~+对酶有激活作用,其余离子均有不同程度抑制作用,而Cu~(2+)和Ca~(2+)抑制作用最强,酶活力减弱近50%,是该酶的强效抑制因子。诱变前后菌株产酶条件和酶学性质等部分表型发生了变化,而突变菌株显示出了更宽泛的环境适应范围。据此,获得一株高效产纤维素酶、耐受范围广的具纤维素降解能力的地衣芽孢杆菌,而CMC-4-3和CMC-4的表型可作为深入探讨基因型变化的线索。
[Abstract]:A highly efficient cellulose degrading strain CMC-4, was obtained from straw returning soil. According to the morphology, physicochemical properties and 16s rDNA sequence analysis of the strain, it was identified as Bacillus licheniformis (Bacillus licheniformis). A stable and high yield cellulase mutant CMC-4-3. was obtained by sodium nitrite mutagenesis. The enzyme production conditions and enzymatic properties of CMC-4 and CMC-4-3 were compared and analyzed. The results showed that the cellulase activity of CMC-4 / CMC-4-3 was 67.5% higher than that of CMC-4, and the optimum conditions for enzyme production were as follows: pH 6.0 at 37 鈩，

本文编号：2238214