Abstract

The strain which degraded steviol glycosides to steviol (STE) was screened and isolated from soil samples. A phylogenetic tree was constructed and used to determine the taxonomic status of the strain. 16S rDNA sequence was ultimately used to identify the strain as Microbacterium barkeri XJ. The transformation product was detected and identified as STE by HPLC/LC-MS/IR analysis. The bioconversion rate of 1% (v/v) steviol glycosides (stevioside, rebaudioside A, rebaudioside C) into STE in basic medium were 100% within 24 h, 84 h and 144 h, respectively. The results indicated XJ was more effective than mixed flora in the bioconversion of steviol glycosides to STE.

摘要

从土壤样品中筛选并分离出将甜菊糖苷降解为甜菊醇 (STE) 的菌株。构建了系统发育树并用于确定该菌株的分类地位。最终使用 16S rDNA 序列将菌株鉴定为巴氏微杆菌XJ。通过HPLC/LC-MS/IR分析检测并鉴定转化产物为STE。1% (v/v) 甜菊糖苷（甜菊苷、莱鲍迪苷 A、莱鲍迪苷 C）在基础培养基中转化为 STE 的生物转化率在 24 小时、84 小时和 144 小时内分别为 100%。结果表明，在甜菊糖苷生物转化为 STE 方面，XJ 比混合菌群更有效。