西藏牦牛瘤胃源产纤维素酶菌株筛选鉴定及产酶条件探究

Screening and Identification of Cellulase Producing Strains from Rumen Source of Tibetan Yaks and Investigation of Enzyme Producing Conditions

为提高纤维素的利用率,寻找到安全性能好、产酶效率高的菌株添加剂添加到饲料中,以提升动物对饲料的利用率,从牦牛瘤胃中分离高产纤维素酶菌株,进行16S rDNA的鉴定,并探究其在不同温度、pH、接种量和发酵阶段产内切型-β-葡聚糖酶、外切型-β-葡聚糖酶、β-葡萄糖苷酶的特性。结果表明:通过形态学鉴定以及16S rDNA基因序列测定,最终确定高产菌株M1为克雷伯氏菌(Klebsiella oxytoca)。M1产内切型-β-葡聚糖酶活性大于外切型-β-葡聚糖酶、β-葡萄糖苷酶;M1在35℃、pH为7、接种量为2%的条件下产内切型-β-葡聚糖酶的效率最高,在30℃、pH为6、接种量为2%的条件下产外切型-β-葡聚糖酶的效率最高,在30℃、pH为6、接种量为1%条件下产β-葡萄糖苷酶的效率最高;在M1生长过程中,先产生了β-葡萄糖苷酶,其次是外切型-β-葡聚糖酶、内切型-β-葡聚糖酶,并且外切酶活性远远大于内切酶和β-葡萄糖苷酶活性。

In order to improve the utilization of cellulose and find the additives of strains with good safety and high enzyme-producing efficiency to be added to the feed to enhance the utilization of feed by animals,high cellulase-producing strains were isolated from the rumen of yaks,identified by 16S rDNA,and explored for the production of endoctyl-β-glucanase,ectoctyl-β-glucanase,β-glucosidase,andβ-glucosidase at different temperatures,pH,inoculum amounts,and fermentation phases.glucosidase.The results showed that the endo-β-glucanase,exo-β-glucanase,andβ-glucosidase production activities of M1 were higher than those of exo-β-glucanase and β-glucosidase,and the endo-β-glucanase was most efficiently produced at 35℃,pH 7,and 2% of the inoculum.glucoamylase at 35℃,pH 7,and an inoculum amount of 2%;M1 produced β-glucosidase at 35℃,pH 7,and an inoculum amount of 2%with the highest efficiency;β-glucosidase was produced first in the growth process of M1,followed by exo-β-glucoamylase and endo-β-glucoamylase,and the exonuclease activity was much greater than the endonuclease and β-glucosidase activities.