瘤胃中纤维素分解菌的分离、鉴定及其产酶条件的优化

Isolation and identification of rumen bacteria for cellulolytic enzyme production

摘要:

摘要:【目的】从新疆细毛羊、牛和骆驼瘤胃液中分离出具有分解纤维素能力的好氧细菌，用于绿色粗饲料微生物添加剂的研发。【方法】采取新鲜瘤胃液，接种于羧甲基纤维素钠平板，通过刚果红染色和液体复筛培养基，筛选出分解纤维素能力强的好氧细菌;形态学、生理生化试验与16S rDNA序列分析方法相结合对细菌进行鉴定;同时对纤维素分解能力强的4株细菌进行不同条件下酶活力测定。【结果】共分离到84株具有分解纤维素能力的细菌，其中筛选出较强分解纤维素能力的40株。该菌包括37株G－菌和3株G+菌;经鉴定40株纤维素分解菌分别属于6个属10个种，其中16株为寡养单胞菌属，10株为苍白杆菌属，5株为鞘氨醇杆菌属，3株为微杆菌属，3株为副球菌属，2株为假单胞菌属。其中产酶能力强的4株菌在不同条件下的酶活力表明，它们在最佳碳源为秸秆粉、pH5.5－6.0的偏中性条件和37℃培养条件下的酶活力较高。不同菌株对不同纤维素类物质的分解能力不一样，同一菌株对不同纤维素碳源的利用能力也不相同。【结论】分离获得的瘤胃纤维素分解菌是从新疆不同地区、干旱半干旱环境下饲养的动物胃液中分离、筛选出来的，有较强的纤维素分解能力，将为高品质、高消化率的青贮饲料生产提供优质菌种资源及一定的科学依据。

Abstract:

Abstract:［Objective］We screened aerobic bacteria with cellulolytic activity from ruminal fluid of sheep，cattle and camel in Xinjiang． ［Method］Fresh ruminal fluid was inoculated on sterilized sodium carboxymethylcellulose agar plates．Highly cellulolytic aerobic bacteria were screened out by using Congo red staining and liquid secondary screening culture media．The combination of morphological and biochemical test with 16SrDNA sequence analysis were used to classify the strains． Enzymatic activities of four strains with strong cellulose-decomposing abilities were studied under different culture conditions．［Results］Out 84 isolated cellulolytic strains，40 exhibited strong abilities in decomposing cellulose． They are including 37 Gram-negative isolates and 3 Gram-positive strains． Identification of these 40 strains shows that they belong to 11 species of 6 genera，16 strains in Stenotrophomonas maltophilia，10 Ochrobactrum，5 Sphingobacterium，3 Microbacterium，3 Paracoccus and 2 Pseudomonas．The results of the enzymatic studies of four strains with strong cellulolytic abilities indicates that the strains have the best enzyme producing property when straw powder was chosen as the carbon source; the pH at 5.5－6.0 and temperature at 37℃．［Conclusion］ The strains with highly cellulolytic abilities isolated from ruminal fluid show strong abilities in cellulose decomposition．