摘要
【目的】从奶牛瘤胃液中分离出具有分解纤维素能力的兼性厌氧细菌，用于绿色粗饲料微生物添加剂的研发。【方法】从奶牛瘤胃中采取瘤胃液，接种于羧甲基纤维素钠平板，采用严格厌氧结合需氧培养方式进行培养，通过刚果红染色，筛选出分解纤维素能力强的兼性厌氧细菌；采用生化试验结合16SrDNA序列分析方法对细菌进行鉴定，并绘制系统发育树；同时对细菌生长特性及有无致病性进行初步测定。【结果】共分离到63株具有分解纤维素能力的细菌，其中29株有较强的分解纤维素能力，包括24株G菌，5株G＋菌；24株G-细菌中，18株为肺炎克雷伯氏菌肺炎亚种，3株为铜绿假单胞杆菌，2株为大肠杆菌，1株为产酸克雷伯氏菌；5株G＋细菌中，2株与苏云金芽孢杆菌有99．7％的同源性，2株与巨大芽孢杆菌有99．6％的同源性，1株与蜡状芽孢杆菌有99．5％的同源性，分类学上可分别归于苏云金芽孢杆菌、巨大芽孢杆菌和蜡状芽孢杆菌。细菌的生长特性及致病性试验表明，分离到的细菌在20-41℃、pH5．O～9．0条件下生长良好，肺炎克雷伯氏菌、苏云金芽孢杆菌和巨大芽孢杆菌无致病性。【结论】分离到的奶牛瘤胃兼性厌氧细菌，可用于绿色粗饲料微生物添加剂的研发。
[Objective] This investigation was conducted to screen facultatively anaerobic cellulolytic bacteria separated from cow ruminal fluid for exploiting Microbial Feed Additives. [Method] Ruminal fluid was spread aseptically on sterilized CMC-Na agar plates, then the plates were incubated under the anaerobic conditions. The isolates dyed by Congo red to form big transparent haloes surrounding the individual colony were selected for identifying. Biochemical characterization and 16S rDNA sequence analysis were used for the classification of the strains. Physiological properties and pathogenicity were also preliminarily studied. [Result] Out of 63 isolated cellulolytic strains, 29 exhibited strong abilities in decomposing cellulose. A- mong 24 Gram-negative isolates, 18 strains were classified as Klebsiella pneurnoniae, 3 Pseudomonas aeruginosa ,2 Escherichia coli and 1 Klebsiella oxytoca. Of 5 Gram-positive isolates, 2 strains belonged to Bacillus thuringiensis, 2 Bacillus megaterium and 1 Bacillus cereus. The screened strains required the most moderate culture conditions at temperature （20--41 ℃） and pH （5--9）. Study of pathogenicity indi- cated that the 3 kinds of isolated bacteria could not cause the death of rats. [Conclusion] The results suggested that the isolated strains could become candidates for Microbial Feed Additives.
出处
《西北农林科技大学学报（自然科学版）》
CSCD
北大核心
2009年第3期35-42,共8页
Journal of Northwest A&F University(Natural Science Edition)
基金
山东农业大学博士后基金项目
