梅花鹿瘤胃纤维素降解菌的分离鉴定及其酶活力测定

为获得来源于梅花鹿瘤胃的高效纤维素降解菌，本试验采集了3锯龄健康梅花鹿的新鲜瘤胃液，用羧甲基纤维素钠（CMC-Na）培养基分离筛选纤维素降解菌，综合其形态学、生理生化特征和16S rDNA基因测序等对分离菌株进行分类学鉴定，利用DNS法对菌株的产纤维素酶条件进行初步研究，并探讨以不同物质为底物时的纤维素酶酶学特性，为后期菌株的应用提供理论数据。结果显示，本试验从梅花鹿瘤胃液中分离的菌株N-11是一株高效纤维素降解菌，经鉴定为蜡样芽孢杆菌（Bacillus cereus）。产酶性质研究结果表明，该菌株产纤维素酶活力在30~45℃（最适温度为40℃），pH为6.0~7.0（最适pH 6.0），碳源含量为2%~5%（最佳接种量5%）较高；培养36 h时达到产酶高峰，纤维素酶酶活力（CMCA）和滤纸酶酶活力（FPA）分别为12.563、12.414 U/mL，在20~50℃或pH 6.0~8.0环境下作用1 h，其相对酶活力均保持在80%以上，稳定性较好。以上结果表明，蜡样芽孢杆菌N-11具有较高的纤维素酶活力，在纤维素利用方面具有较高的应用价值。

Isolation,Identification and Determinations of Cellulose-degrading Bacteria from Sika Deer (Cervus nippon) Rumen

In order to obtain strains with higher cellulose-degrading ability isolated from Sika deer (Cervus nippon) rumen,the fresh rumen liquid was collected from Sika deer,and CMC-Na medium was used to isolate and screen strains,and the morphological,physiological and biochemical characteristics and 16S rDNA gene sequence were analyzed to identify the taxonomic position of the strains.Moreover,the cellulose producing conditions of the strain was preliminarily studied by DNS method,and the characteristics of cellulose production with different substances as substrates were studied in order to provide theoretical basis for the application of strain.The results showed that N-11 strain was a highly efficient cellulose-degrading bacteria,which was identified as Bacillus cereus.The properties of the cellulose production showed that when the fermentation temperature ranged from 30 to 45℃ (optimum at 40℃),pH was 6.0 to 7.0 (optimum at 6.0),and carbon source content was 2% to 5% (optimum at 5%),it had the higher enzyme activity.In addition,when cultivated for 36 h,the peak of cellulose production was reach which CMC cellulose activity of N-11 strain was 12.563 U/mL and FPA cellulose activity was 12.414 U/mL.The relative cellulose activity still retained above 80% at 20 to 50℃ or pH 6.0 to 8.0 when cultivated for 1 h.These results indicated that N-11 strain had a high cellulose productivity,and it might have some potential for industrial applications.