降解纤维素真菌的分离筛选及其环境适应性初探

Isolation and Screening of Cellulose-decomposing Microorganisms and Their Adaptability to Some Environmental Factors

为获得有强降解纤维素能力的真菌,以羧甲基纤维素钠培养基为基础培养基,从采集的秸杆、牛粪等样品中进行分离筛选,获得具有分解纤维素能力的9株真菌菌株。采用羧甲基纤维素钠刚果红培养基进行粗选,初步得到6株透明水解圈较大的菌株。将所有待测真菌菌株进行液体发酵培养,测定其滤纸崩溃度及羧甲基纤维素钠酶活力,得到2株分解纤维素能力较强的优良菌株,命名为F-1,F-6。对这2株菌株进行碳源、氮源、pH值和培养时间的适应性研究及混合发酵培养的简单研究。结果发现,F-1菌株在碳源为滤纸,氮源为硝酸铵时,具有最佳产酶效果,而其最适产酶pH为6.5～7,最适产酶时间为6～7d。F-6菌株与其类似。混合发酵的最佳产酶时间为6～8d。通过鉴定可知2株菌都属于头孢霉属(cephalosporium corda)。

To obtain effective cellulose-decomposing fungi, sodium carboxymethyl cellulose was used as media to isolate and screen. 9 strains of fungi for decomposing cellulose were isolated from straw and cow manure. 6 strains showed a great capacity in cellulose decomposing, indicated by large and distinct red circles around the colonies in Congo red agar medium. Tow strains of fungi which had better capacity to decompose cellulose were obtained through the experiments of decomposition of filter paper, determinations of CMC enzyme activity using liquid fermentation. They were named F-1 and F-6. The strains were studied on the adaptability to carbon sources, nitrogen source, pH, the culture time and mixed fermentation. The results showed that F-1 had the best performance enzyme producing property when filter paper was chosen as the carbon source, ammonium nitrate as the nitrogen source, the pH was chosen as 6.5-7 and the culture time scale for it was set in 6-7 days. F-6 was similar to the F-1. The cuhure time scale for mixed fermentation was set in 6-8 days. Through identification these two strains belongs to cephalosporium corda.