高产几丁质酶巴伦葛兹类芽孢杆菌的筛选和发酵条件优化

【目的】鉴定一株来源于中国南海海水样能够分泌多种胞外几丁质酶的类芽孢杆菌CAU904,并优化其产几丁质酶的发酵条件。【方法】采用形态学观察、16S r DNA序列比对及生理生化实验鉴定;通过碳源、氮源、温度、初始p H、表面活性剂种类以及发酵时间的单因素优化实验获得最佳发酵条件。【结果】菌株CAU904被鉴定为巴伦葛兹类芽孢杆菌(Paenibacillus barengoltzii),其最优发酵产酶条件为:0.5%胶体几丁质,0.2%酵母浸提物,0.1%吐温-80,培养基初始p H 7.0,45°C培养72 h。在最优发酵条件下,该菌株最大产酶水平达到8.2 U/m L,比优化前提高了5.4倍。几丁质酶的酶谱分析表明该菌株能够产生多达11种具有几丁质水解活性的同工酶,其中主要酶谱带对应分子量分别为54、47和38 k D。【结论】实验结果为巴伦葛兹类芽孢杆菌几丁质酶的分离纯化和酶的应用提供了基础。

Screening of a high-level chitinase producing strain, Paenibacillus barengoltzii and optimization of its fermentation conditions

Objective] To identify a chitinase producing marine bacterium CAU904 isolated from China Nan Hai and optimize the fermentation conditions for chitinase production. Methods] Strain CAU904 was identified based on its morphological characters and 16S rDNA sequence. The fermentation conditions for chitinase production by strain CAU94 were optimized using the one-factor-at-a-time method. Results] The strain CAU904 was identified as Paenibacillus barengoltzii, and the optimal fermentation conditions were obtained as follows: 0.5% colloidal chitin, 0.2% yeast extract, 0.1% Tween 80 (medium pH 7.0) 45 °C for 72 h. Under the optimized fermentation conditions, the highest chitinase activity of 8.2 U/mL was achieved, which was 5.4 folds higher than that obtained before. The chitinase zymogram analysis showed that at least 11 chitinases were secreted into the fermentation broth, and three major bands had molecular masses of 54, 47 and 38 kD, respectively. Conclusion] The results can be helpful for further study on the purification and application of the chitinases from Paenibacillus barengoltzii.