一株产几丁质脱乙酰酶海洋细菌的Rhodococcus hoagii筛选、鉴定及酶学性质

Screen,identification and enzymatic properties of a marine bacteria strain producing chitin deacetylase

从连云港高公岛海域采集的海泥中使用平板变色圈法初筛和摇瓶发酵复筛后,获得一株产几丁质脱乙酰酶的菌株MCDAⅡ-2。综合形态学特征以及16SrDNA序列分析最终将菌株MCDAⅡ-2鉴定为Rhodococcus hoagii。进而研究其酶学性质,得该几丁质脱乙酰酶最适催化温度为35℃,最适pH为8.0。Na^+、Mg^2+、Li+、Sr^2+对酶促反应起到促进作用,Ca^2+、Ba^2+、Co^2+、Cd^2+、Fe^2+及EDTA对酶促反应起到了抑制作用,而K^+对酶促反应影响较小。酶在25℃~35℃时较稳定,在中性和弱碱性条件下稳定性较好。本次研究的结果将为几丁质脱乙酰酶的工业化应用奠定基础。

MCDAⅡ-2,a chitin-deacetylase-producing strain,was screened from sea mud collected from Gaogong Island in Lianyungang by flat-plate color circle method and re-screened by flask shaking fermentation.The strain MCDAⅡ-2 was identified as Rhodococcus hoagii based on morphological characteristics and 16 S rDNA sequence analysis.Optimum temperature 35℃and pH of chitin deacetylase was 8.0 respectively.Metal ions such as Na^+,Mg^2+,Li+and Sr^2+were found to improve the enzyme activity compared to a control.The experiment also showed that Ca^2+,Ba^2+,Co^2+,Cd^2+,Fe^2+can enhance the enzyme activity,while EDTA and K^+had little effect.The enzyme performed well in a temperature range of 25℃~35℃,with good stability under neutral and weak base conditions.The results of this study will lay a foundation for the industrial application of the enzyme.