摘要
为筛选牦牛粪便中高效纤维素降解菌,实现高纤维素类饲料资源化利用。利用刚果红平板染色法初筛,纤维素酶活测定复筛,从甘肃省天祝县牦牛粪便中分离产纤维素酶菌株,并结合形态学观察、生理生化特征和16S rDNA基因序列同源性分析进行鉴定。对菌株培养时间、温度、初始pH、接种量条件进行单因素优化,并在优化的基础上采用响应面优化,将优化后纤维素酶液处理小麦、玉米和水稻秸秆,10 d后检测秸秆降解率。结果表明:分离筛选出1株产纤维素酶菌株M2,鉴定为Bacillus pumilus;初步确定该菌株发酵产纤维素酶最佳工艺条件为温度33℃、初始pH 6.5、接种量5%、培养时间30 h,羧甲基纤维素酶活最高为520 U/mL,与优化前相比提高了1.3倍;滤纸酶活为98 U/mL,与优化前相比提高了1.1倍;玉米秸秆的降解效果优于其他2种秸秆,玉米秸秆纤维素、半纤维素和木质素的降解率分别为36.2%、25.5%和4.3%。
To identify high efficient cellulose degrading bacteria from faeces of yak and promote high fiber feed utilization in Tianzhu Country,Gansu Province,high-yielding cellulase strains were isolated from the feces of yak firstly by the methods of Congo red staining method and then by cellulase activity analysis.Morphological observation,physiological and biochemical characterizations and the analysis of 16 S rDNA sequences alignment were conducted for further identification.The culture time,culture temperature,initial pH and inoculation size were optimized by single factor analyses and Box-Behnken design was then adopted on the basis of optimization.Wheat,corn and rice straws were treated with optimized cellulase solution,and the degradation rate of straws was measured 10 days after treatment.The results showed that a high-yielding cellulase strain M2 was isolated and identified as Bacillus pumilus.The optimum conditions for M2 to produce cellulase were shown as follows:Culture temperature 33 ℃,initial pH 6.5,inoculum size 5% and culture time 30 h.Under the optimum condition,its CMCase activity reached 520 U/mL,which was 1.3 times higher than before and the FPAse activity was up to 98 U/mL,which was 1.1 times higher than before.The degradation rate for corn straw was better than the other two types of straws.The degradation rates of cellulose,hemicellulose and lignin of corn stalk were 36.2%,25.5% and 4.3%,respectively.
作者
毛婷
魏亚琴
杨红建
牛永艳
陈娟
王治业
MAO Ting;WEI Yaqin;YANG Hongjian;NIU Yongyan;CHEN Juan;WANG Zhiye(Institute of Biology,Gansu Academy of Sciences,Lanzhou 730000,China;Key Laboratory of Microbial Resources Exploitation and Application,Lanzhou 730000,China;College of Animal Science and Technology/State Key Laboratory of Animal Nutrition,China Agricultural University,Beijing 100193,China)
出处
《中国农业大学学报》
CAS
CSCD
北大核心
2019年第11期106-116,共11页
Journal of China Agricultural University
基金
甘肃省基础研究创新群体项目(1606RJIA325)
甘肃省科学院创新团队项目(CX201601)
甘肃省科学院青年科技创新基金项目(2017QN-04)
甘肃省科学院应用研发项目(2018JK-07).
