角质降解细菌筛
发布时间：2018-11-26 16:14
【摘要】：植物表面覆盖的角质层不易透水、透气、耐酸碱、耐氧化,是植物细胞壁与周围环境之间的物理和化学屏障,也一定程度影响了植物纤维的消化。角质层主要组成成分为角质,可被角质酶高效降解,且反应温和、无污染。本研究旨在筛选降解角质能力较强的菌株,并对其产酶发酵条件和胞外粗酶酶学性质进行探讨,为降解植物角质层,改善动物对植物纤维利用提供指导。高效角质降解菌筛选:采用番茄角质和角质类似物聚己内酯(PCL)-指示剂变色圈法从混合植物堆肥、动物粪便及病害果蔬表面分离角质降解菌,筛选到8株降解角质能力较强的菌株,分别命名为L3-2、L14、L16L、X3PB、X3PH、X4、X8P、X16。进一步比较各菌株在角质诱导下发酵生产胞外酯酶活性大小,成功获得2株角质降解能力较突出的菌株L3-2和X8P,经形态观察和分子鉴定分别为Klebsiella pneumoniae L3-2和Acetobacter orientalis X8P。Klebsiella pneumoniae L3-2和Acetobacter orientalis X8P发酵条件优化:结果表明,菌株L3-2在LB培养基中40℃、发酵3d产酶能力最强,1%玉米芯和0.5%牛肉膏明显促进L3-2产酶(P㩳0.05)。菌株X8P在LB培养基中37℃、发酵4d产酶能力最强,1%橄榄油明显促进X8P产酶。1%可溶性淀粉对两菌株产酶有强抑制作用,而1%葡萄糖促进两菌株产酶。菌株Klebsiella pneumoniae L3-2和Acetobacter orientalis X8P酯酶粗酶学性质研究:结果表明,菌株L3-2胞外酯酶粗酶最适pH和温度分别为pH 6.5和55℃,pH稳定性不好。有机溶剂大都对其有抑制作用,甲醇(50%)和DMSO(50%)对其有促进作用(分别提高0.92倍和1.85倍)。甘油(50%和80%)对其有强激活作用(分别提高2.4倍和4.98倍)。Tween-20及Triton-100(1 mM和10 mM)可使L3-2胞外酯酶粗酶活提高2%-10%。金属离子Na~+、Mg~(2+)、Mn~(2+)、Ca~(2+)、Ba~(2+)(1mM和10 mM)可使L3-2胞外酯酶活性提高2%-31%。菌株X8P胞外酯酶粗酶最适pH和温度分别为pH 6.5和45℃,且有一定pH稳定性,但在多数有机试剂中不稳定,只在甘油中保留全部活性,在DMSO(50%)中活性保留66%。Tween-20(1 mM)、Tween-80(1 mM)和Triton-100(1 mM和10 mM)可使X8P酯酶粗酶活性提高3%-35%。金属离子K~+、Mn~(2+)(1 mM和10 mM)可使X8P粗酶活性提高2%-20%(P㩳0.05)。
[Abstract]:The cuticle covered on the plant surface is not permeable, breathable, acid-alkali resistant and oxidized. It is a physical and chemical barrier between the cell wall of plant and the surrounding environment, and also affects the digestion of plant fiber to some extent. The keratinocytes are mainly composed of keratinocytes, which can be degraded efficiently by keratinases, and the reaction is mild and pollution-free. The purpose of this study was to screen the strains with strong ability to degrade keratinocytes, and to investigate the fermentation conditions and the enzymatic properties of extracellular crude enzymes, so as to provide guidance for the degradation of plant keratinocytes and the improvement of animal utilization of plant fibers. Screening of high efficient keratinizing bacteria: the keratinized bacteria were separated from the surface of mixed plant compost, animal feces and fruits and vegetables by (PCL) indicator method. Eight strains with strong keratolytic ability were selected and named L3-2L14L14 L16LBX3PHPX4X8PX16X16. The results showed that there were 8 strains with strong keratinolytic ability, and they were named L3-2L14, L16, L16 and L16, respectively. Two strains L3-2 and X8P were successfully obtained by comparing the extracellular esterase activity of each strain under keratinocyte induction fermentation. After morphological observation and molecular identification, the fermentation conditions of Klebsiella pneumoniae L3-2 and Acetobacter orientalis X8P.Klebsiella pneumoniae L3-2 and Acetobacter orientalis X8P were optimized, respectively. The results showed that the strain L3-2 was most capable of producing enzyme for 3 days after fermentation at 40 鈩，
本文编号：2359028
[Abstract]:The cuticle covered on the plant surface is not permeable, breathable, acid-alkali resistant and oxidized. It is a physical and chemical barrier between the cell wall of plant and the surrounding environment, and also affects the digestion of plant fiber to some extent. The keratinocytes are mainly composed of keratinocytes, which can be degraded efficiently by keratinases, and the reaction is mild and pollution-free. The purpose of this study was to screen the strains with strong ability to degrade keratinocytes, and to investigate the fermentation conditions and the enzymatic properties of extracellular crude enzymes, so as to provide guidance for the degradation of plant keratinocytes and the improvement of animal utilization of plant fibers. Screening of high efficient keratinizing bacteria: the keratinized bacteria were separated from the surface of mixed plant compost, animal feces and fruits and vegetables by (PCL) indicator method. Eight strains with strong keratolytic ability were selected and named L3-2L14L14 L16LBX3PHPX4X8PX16X16. The results showed that there were 8 strains with strong keratinolytic ability, and they were named L3-2L14, L16, L16 and L16, respectively. Two strains L3-2 and X8P were successfully obtained by comparing the extracellular esterase activity of each strain under keratinocyte induction fermentation. After morphological observation and molecular identification, the fermentation conditions of Klebsiella pneumoniae L3-2 and Acetobacter orientalis X8P.Klebsiella pneumoniae L3-2 and Acetobacter orientalis X8P were optimized, respectively. The results showed that the strain L3-2 was most capable of producing enzyme for 3 days after fermentation at 40 鈩，
本文编号：2359028
本文链接：https://www.wllwen.com/yixuelunwen/dongwuyixue/2359028.html
