1株饲用黑曲霉的分离鉴定及其纤维素酶活性检测

Isolation and identification of a cellulose-degrading Aspergillus niger strain from fermented feed and detection of its activity

试验旨在从发酵饲料的微生物中筛选分离鉴定能够高效降解纤维素的曲霉菌株。试验利用PDA培养基对黑曲霉进行分离,通过菌株形态特征和ITS序列分析鉴定分离菌株,构建系统发育树,判定菌株分类地位;检测该菌的菌落形态和生长特性,定性研究该菌的酶谱,选择不同碳源诱导其产内切葡聚糖酶、滤纸酶及木聚糖酶活的变化。结果显示,试验采用PDA培养基分离培养得到1株曲霉,经鉴定该菌为黑曲霉,编号为0729。在接种量为5%、发酵温度30℃,培养第2 d,由木糖诱导黑曲霉产内切葡聚糖酶活和滤纸酶活最高,培养第1 d滤纸诱导的木聚糖酶活最高。研究表明,发酵饲料中富含可降解纤维的微生物资源,黑曲霉可以产纤维素酶、淀粉酶和脂肪酶,对开发反刍动物饲用微生物具有重要作用。

The study was to screen,isolate and identify Aspergillus niger strains that could efficiently degrade cellulose from microorganisms in fermented feed.Aspergillus niger was isolated by PDA medium.The isolated strains were identified by morphological characteristics and ITS sequence analysis,and the phylogenetic tree was constructed to determine the taxonomic status of strains.The colony morphology and growth characteristics of the strain were detected,and the zymogram of the strain was qualitatively studied.Different carbon sources were selected to induce the activity of endoglucanase,filter paper enzyme and xylanase.The results showed that one Aspergillus strain was isolated and cultured by PDA medium,which was identified as Aspergillus niger,and the number was 0729.When the inoculum size was 5%and the fermentation temperature was 30℃,the highest endoglucanase activity and filter paper enzyme activity were induced by xylose on the 2rd day,and the highest xylanase activity was induced by filter paper on the 1st day.The study indicates that fermented feed is rich in microbial resources that can degrade fiber,and Aspergillus niger produces cellulase,amylase and lipase,which is of great value to develop feeding microorganisms for ruminants.