一株酯化功能菌分离鉴定及酶学特性研究

Identification and enzymatic properties of an excellent esterifying function strain

从国家级重点文物遗产"国宝窖池"中分离选育得到一株高酯化力的发酵功能菌。结合形态学特征和分子解析对其进行了鉴定。菌落在麦芽汁琼脂培养基上初为白色随菌落成熟而变成粉红色,表面质地呈丛卷毛状。菌丝不规律地分枝,菌丝体顶端着生闭囊壳。酶学特性研究结果显示:所产酯化酶最适作用温度为30℃,最适pH为5.0,金属离子Na+、K+、Mg2+、Fe2+对该酶有明显的促进作用,而Ca2+、Cu2+对该酶有强烈的抑制作用。扩增菌株的内转录间隔区ITS序列,长度579bp。利用Gene Bank BLAST搜索同源序列,通过DNAMAN分别进行序列相似性比对。其中ITS序列与Monascus purpureus典型菌株相似性高达99.5%,DNAstar分析显示两者的离散度为0.5%,Mega构建NJ系统进化树,处于进化树同一分支。根据形态学特征以及分子解析结果,基本可以判定该菌株为Monascus属purpureus种的一株新型优势菌株,命名为Monascus purpureus LZLJ2103。

An excellent esterifying function strain LZLJ 2103 was isolated and bred from ＇ 1573 National Treasures cellars＇ ,which was identified by combining the morphological and molecular characteristics.After incubation for 7d,the white colony of LZLJ 21-3 became pink gradually as time went on.Colony surface clustered around curly mycelia.ln the top of mycelium was the cleistothecium.The study of enzymatic properties of esterase from the strain showed that the optimal temperature for the enzyme was 40℃ and optimal pH was 5.0. Na ＋ , K＋ , Mg2＋ , Fe2＋ enhanced the enzyme activity, whereas Ca2＋ , Cu2＋ inhibited the enzyme activity significantly. Internal transcribed spacers were amplified and sequenced.The 579bp sequence was compared with the known sequences in the GenBank database.Sequence alignment analysis has been done by bioinformatics software DNAMAN, DNAstar and Mega.The similarity of ITS between LZLJ 2103 and typical strain of Monascus purpureus was 99.5% and the divergence 0.5%.The phylogenetic analysis by NJ test showed that LZLJ 2103 came together with the known strains,which showed the highest similarity.According to morphological features and molecular analysis could draw the conclusion that LZLJ 2103 was belonged to one new strain of the Monascus purpureus.