| 吴佳勇,封孝兰,曾德军,谌颖莲,竭航.2022.麝鼠肠道纤维素分解菌的分离鉴定及其酶学特性分析.动物学杂志,57(1):143-151. |
| 麝鼠肠道纤维素分解菌的分离鉴定及其酶学特性分析 |
| Isolation, Identification and Enzymatic Characteristics of Cellulolytic Bacteria from the Intestinal Tract of Muskrats |
| 投稿时间：2021-08-06 修订日期：2022-01-05 |
| DOI：10.13859/j.cjz.202201015 |
| 中文关键词: 麝鼠 纤维素分解菌 羧甲基纤维素酶 |
| 英文关键词:Muskrat Cellulose-decomposing bacteria Carboxymethyl cellulase |
| 基金项目:重庆市基本科研业务费项目（No. cstc2020jxjl-jbky130002），国家自然科学基金项目（No. 81973428） |
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| 中文摘要: |
| 本研究旨在从麝鼠（Ondatra zibethicus）肠道中分离出高效分解纤维素的菌株，为开发纤维素分解菌微生物制剂提供菌种资源。本研究利用以羧甲基纤维素钠（CMC-Na）为单一碳源的培养基，从麝鼠盲肠内分离出一株高效分解纤维素的菌株WJ-3，并对该菌株进行形态鉴定、生理生化鉴定和16S rDNA分子鉴定。对菌株WJ-3所产羧甲基纤维素酶（CMCase）进行酶学特性实验，分析此纤维素酶的最佳反应pH和最佳反应温度，以及此纤维素酶对不同温度和不同酸碱度的耐受性。结果表明，菌株WJ-3属于空气芽孢杆菌（Bacillus aerius），并将其命名为Bacillus aerius WJ-3。菌株WJ-3所产羧甲基纤维素酶在pH 4.0 ~ 6.0的范围内反应时，酶活性随pH值升高而增加，其最佳反应pH为6.0，且此纤维素酶在pH 4.0 ~ 8.0范围内保存30 min后均能保持80%以上的相对酶活性；菌株WJ-3所产羧甲基纤维素酶在温度30 ~ 50 ℃范围内反应时，随温度上升酶活性逐渐增加，在50 ℃时酶活性最高，之后随温度的升高酶活性逐渐下降，且纤维素酶在此温度范围内保存30 min后均能保持较高的酶活性。综上所述，菌株Bacillus aerius WJ-3所产羧甲基纤维素酶的酶活性较高，并且此纤维素酶的耐酸碱性及热稳定性良好，是具有一定利用价值的菌种资源。 |
| 英文摘要: |
| [Objectives] The purpose of this study was to isolate strains capable of efficiently decomposing cellulose from the intestines of Muskrat (Ondatra zibethicus), so as to provide strain resources for the development of microbial preparations of cellulose decomposing bacteria. [Methods] Six cellulose decomposing bacteria were isolated from the cecum of Muskrat using the culture medium with sodium carboxymethyl cellulose (CMC-Na) as the only carbon source. The Congo red staining experiment and the determination of carboxymethyl cellulase (CMCase) activity were carried out. Bacterium strain WJ-3 with highly efficient cellulose decomposing activity was screened, and further identified by morphological observation, physiological and biochemical analysis as well as 16S rDNA gene sequencing approach. The 16S rDNA gene sequence was analyzed by BLAST in national center for biotechnology information (NCBI), and the phylogenetic tree was constructed by MEGA 6.0 software. The enzymatic characteristics of CMCase produced were tested to analyze the optimal reaction pH and temperature of the cellulase, as well as the tolerance of the cellulase to different temperatures and pH values. Ultimately, all the data were processed with Spss 23.0 software. [Results] A strain WJ-3 with efficient cellulose decomposing activity was identified and it was agram-positive, spore-forming, and rod-shaped bacterium (Fig. 2, Fig. 3). The physiological and biochemical test results of strain WJ-3 were shown in Table 2. By the 16S rDNA gene sequence analysis, strain WJ-3 was identified as Bacillus aerius, and named Bacillus aerius WJ-3 (GenBank Accession: MZ 292092.1). The phylogenetic tree of strain WJ-3 was shown in Figure. 5. When the CMCase produced by strain WJ-3 reacted in the range of pH 4.0﹣6.0, the enzyme activity increased with the increase of pH value, and the best reaction pH was 6.0 (Fig. 6), and the cellulase could maintain more than 80% of the relative enzyme activity after being stored in the range of pH 4.0﹣8.0 for 30 min (Fig. 7); When the CMCase produced by strain WJ-3 reacted in the temperature range of 30﹣50 ℃, the enzyme activity gradually increased with the increase of temperature, the enzyme activity was the highest at 50 ℃ (Fig. 8), and then the enzyme activity of CMCase decreased with the increase of temperature, the cellulase could maintain high enzyme activity after being stored in the temperature range of 30﹣50 ℃ for 30 min (Fig. 9). [Conclusion] The enzyme activity of CMCase produced by strain Bacillus aerius WJ-3 is relatively high, with satisfactory acid and alkali resistance as well as thermal stability. It is a strain resource with certain utilization value. |
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