摘要
【目的】从堆肥中筛选和鉴定产碱性纤维素酶的菌株，对菌株及其酶学特性进行研究。【方法】以刚果红平板染色法进行初筛，摇瓶发酵复筛，分离到高酶活菌株C73。通过形态观察和16SrRNA序列分析对菌株进行鉴定。采用DNS定糖法测定发酵液酶活最适pH值、pH值稳定性、最适温度、热稳定性及常见金属离子、SDS、EDTA等对酶活的影响。[结果]该菌株形态呈杆状，革兰氏阳性，不产芽孢，适宜在pH值8．0～11．0、30～37℃条件下生长。16SrRNA序列比对发现，该菌株与琼斯氏菌（Jonesiasp．）PCI序列相似度大于99％，初步鉴定为琼斯氏菌属菌株。在发酵培养基中，菌体浓度和CMCase活力分别在40h和50h达到最大值，随着发酵时间的延长发酵液pH值稳定在9．5左右。粗酶液的最适作用pH值为10．0，此时CMCase活力达2．3U／mL。在pH值8．0～11．0的范围内保持60％以上的酶活；最适作用温度为60℃，且在30-80℃的范围内保持60％以上的酶活。金属离子Mn^2＋、Co^2＋和（NH4）2SO4对酶活力有较强的抑制作用。【结论】菌株C73呈现较高的碱性CMCase酶活、较高的热稳定性和pH值稳定性，具有良好的工业应用前景。
[ Objective ] Strain with alkaline CMCase-producing ablities was screened from compost heaps and identified. Studies were conducted on the strain and its enzymatic characters. [MethodlStrain C73 was screened primarily through Congo-red agar plates and secondly by flask fermentation. The strain was identified by rnorphism speculation and 16S rRNA sequence analysis. Enzymatic properties of optimal activity pH, pH stablity, optimal activity temperature and thermo-stablity as well as influence of metal ions,SDS and EDTA on the enzyme were determined throuth DNS method. [Result]The strain was rod- shaped, grampositive, nonsporulating and could grow at pH 8.0-11.0,30-37℃. Fermentation with CMC media showed maxium cell growth and CMCase avtivity peaks were reached at 40h and 50h,with the pH of system decreased to 9. 5. Optimal CMCase activity pH was 10. 0, while the CMCase activity reached 2. 3U/mL. 60% of CMCase activity was obtained at the pH range of 8.0-11.0. Optimal CM- Case activity temperature was 60℃ and 60% of residual CMCase activity was obtained after incubation at 30-80℃ for 1 h. The addition of Mn^2＋, Co^2＋ and （NH4）2 SO4 strongly inhibited CMCase activities. [Conclusion]Strain C73 exhibited higher alkaline CMCase activity, higher pH stablity and thermo-stablity and had a potential in industrial application.
出处
《广西科学》
CAS
2014年第1期28-33,共6页
Guangxi Sciences
基金
国家973项目(2010CB736209)
国家863项目(2012AA022106)
国家国际合作项目(2010DFB63590
2011DFA61910)
广西科学研究与技术开发计划项目(桂科合10100019-21
桂科攻1099071
桂科合1140010-15)
广西自然科学基金项目(2012GXNSFAA053062)
广西科学院基本科研业务费项目(11YJ24SW08)
广西科技创新能力与条件建设计划项目(桂科能12237022)
广西科学基金项目(13-051-08)资助
关键词
纤维素酶
琼斯氏菌
酶学性质
cellulase, Jonesia sp. ,enzymatic properties
