纤维素降解菌的筛选及其产酶特性
Screening of a cellulose-degrading strain and its enzyme-producing conditions
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摘要: 纤维素降解菌在纤维素类物质降解的过程中起着重要作用。通过滤纸条崩解和液态产酶实验，从腐烂的树叶中筛选出1株对纤维素有较强降解能力的菌株SY2，通过形态学特征以及生理生化反应，初步鉴定该菌株为荧光假单胞菌（Pseudomonas fluorescent）。产酶培养基及培养条件优化的实验结果表明：SY2的最佳产酶培养基为麸皮与秸秆粉的质量比1∶4、(NH4)2SO4 1%、pH 8、固液比1∶2；最佳产酶条件为培养温度30℃、接种量7.5%、培养时间72 h；在酶液中添加Fe2+ 和VB12可使纤维素酶活力分别达到174.89 μmol/(g·min)和165.99 μmol/(g·min)，提高了33.5%和26.3%。SY2对麸皮、滤纸的降解效果较好，降解率分别达到45%和33.3%。Abstract: Cellulosedegrading bacteria play an important role in degradation of cellulose material.A strain was screened from the decaying leaves by slaking test with filter paper and liquid enzymeproducting test， designated as SY2.The strain was identified as Pseudomonas fluorescent preliminarily by the way of biochemical identification and morphological characteristics. The experiments were carried out for optimizing the conditions of solid enzyme production . The results showed that the mass ratio of bran to straw and that of solid to liquid are 1 to 4 and 1 to 2. Besides, the concentration of (NH4)2SO4 is 1 %, and pH value is 8. Meanwhile the optimal conditions of enzyme generation include that the culture temperature is around 30℃, the inoculum concentration is 7.5% and culture time is 72 h. Adding Fe2+ and VB12 into enzyme liquid, the activities of cellulase reach 174.89 μmol/(g·min) and 165.99 μmol/(g·min), which are improved by 33.5% and 26.3%， respectively. SY2 degraded bran and filter paper effectively,and the rates of degradation are 45% and 33%,respectively.
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Key words:
- Pseudomonas fluorescent /
- cellulase /
- coenzyme /
- enzyme activity
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