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葫芦素B(CuB)是临床用于治疗肝炎和肝癌等疾病的药物,开发以葫芦素B葡萄糖苷(CuBg)为原料生产CuB的生物转化工艺,具有潜在的工业应用价值,获得一株特异性产酶菌株是转化工艺开发的首要工作。首先利用甜瓜蒂和污水富集培养产酶菌株,平板分离法获得纯培养;之后以含CuBg的甜瓜蒂提取物为底物,筛选出能将CuBg转化为CuB高产菌株,并对筛选获得的菌株进行分类鉴定;最后对转化工艺进行优化,提高转化率。结果分离到一株编号为RW-2放线菌菌株,其滤除菌丝的发酵液处理甜瓜蒂提取物,其中的CuBg被转化为CuB,CuB的含量显著提高;经形态学鉴定和16S r DNA序列分析,确定该菌株是一株链霉菌(Streptomyces sp.);经过转化工艺优化后,该菌株发酵制备的粗酶液转化甜瓜蒂提取物,其中CuB的含量从1.50 g/L提高到3.27 g/L,提高了1.18倍,CuB的转化得率达99.5%。利用生物转化法将低活性的CuBg转化高活性的CuB,具有反应条件温和、工艺简单,转化得率高的优点,在药物CuB生产中有一定的应用价值。
Cucurbitacin B (CuB) is a clinically used drug for the treatment of diseases such as hepatitis and liver cancer, and the development of a bioconversion process for producing CuB from cucurbitacin B glucoside (CuBg) has the potential value of industrial application to obtain a specific Enzyme-producing strains of the transformation process development priorities. First, the enzyme-producing strain was enriched by using Cantaloupe and sewage enrichment, and the pure culture was obtained by the plate separation method. After CuBg-containing melon extract was used as a substrate, CuBg was transformed into CuB-producing strain and the selected strains For classification and identification; finally, the conversion process is optimized to improve the conversion rate. Results A strain of actinomycete RW-2 was isolated and its mycelium-filtered fermentation broth was used to treat the extract of Cucurbita petiole, CuBg was transformed into CuB, and the content of CuB was significantly increased. Morphological identification and 16S r DNA sequence analysis showed that the strain was a Streptomyces sp. After optimization of the transformation process, the crude enzyme solution prepared by fermentation of the strain was transformed into Cantaloupe extract, in which the CuB content increased from 1.50 g / L to 3.27 g / L, an increase of 1.18 times, CuB conversion rate of 99.5%. The transformation of low activity CuBg into high activity CuB by bioconversion method has the advantages of mild reaction conditions, simple process and high conversion rate, and has certain application value in the production of drug CuB.