酸性土壤中高效半纤维素降解菌的筛选与鉴定

摘要

[Objective ] The aim of this study was to screen hemicellulose degrading microorganisms. [Methods] The methods used to screen the effective strains included hydrolysis spot diameter measurement of hemicellulose plate and extracellular enzyme activity. The methods used to identify the strains included culture characteristics, morphological, physiological-biochemical characteristics and molecular biological methods. [ Results ] We isolated 4 actinomycetes (NA9, NA10, NA12 and NA13) , 2 fungi (NF1 and NF7) with hemicellulose degrading ability and no antagonistic effect among them. The hemicellulose degrading activity of 4 actinomyces ( NA9, NA10, NA12 and NA13) was 217. 6, 229. 8, 221. 1 and 211. 8 U/mL. The hemicellulose degrading activity of 2 fungi ( NF1 and NF7 ) was 217. 7 and 244. 2 U/mL. The hemicellulose degrading activity of complex microbial system was 299. 0 U/mL. NA9, NA10, NA12 and NA13 were Streptomyces costaricanus; NF1 was Aspergillus Candidas and NF7 was Tarlaromyces flavus. [ Conclusion ] the 4 actinomyces and 2 fungi screened have high hemicelluloses enzyme activity. These strains have good application value and more research value.%[目的]筛选能够适应南方酸性土壤的高效半纤维素降解菌株,并进行鉴定,确定菌株的安全性.[方法]采用半纤维素平板水解圈法和胞外酶测定法进行菌株筛选,通过拮抗实验构建复合微生物菌系.利用培养特征、形态学、生理生化特征和分子生物学方法进行菌株鉴定.[结果]筛选出效果稳定,互不拮抗的高效半纤维素降解放线菌4株(NA9、NA10、NA12和NA13),半纤维素酶活分别为:217.6、229.8、221.1和211.8 U/mL.真菌2株NF1和NF7,半纤维素酶活为217.7和244.2 U/mL.复合微生物菌系半纤维素酶活可达299.0 U/mL.经鉴定菌株NA9、NA10、NA12和NA13为链霉菌中的哥斯达黎加链霉菌(Streptomyces costaricanus).菌株NF1为亮白曲霉(Aspergillus candidus),菌株NF7为黄蓝状菌(Tarlaromyces flavus).