Department of Biology, Faculty of Sciences, University of Isfahan, Azadi Sq., Daneshgah St., 81746-73441, Isfahan, IR Iran.
Curr Microbiol. 2011 Mar;62(3):990-8. doi: 10.1007/s00284-010-9815-y. Epub 2010 Nov 19.
Candida galli strain PGO6 isolated from oil-contaminated water is the first isolated yeast strain which is capable to form vanillin and vanillic acid during isoeugenol biotransformation. The products were confirmed by thin-layer chromatography (TLC), changes in the UV absorption pattern and high-performance liquid chromatography (HPLC). The phenotypic and physiochemical characteristics as well as molecular phylogenetic analysis based on amplification the ITS1-5.8S-ITS2 rDNA regions indicated the isolated strain PGO6 was identified as C. galli (GenBank accession number HM641231). Resting cells of C. galli PGO6 from the late-exponential of growth phase were used as biocatalysts for the biotransformation of isoeugenol. The optimal molar conversion of vanillin (48%) and vanillic acid (19%) was obtained after a 30 h incubation using 0.1% (v/v) of isoeugenol and 6 mg of dry weight of cells per ml without further optimization. Under these conditions, the total amount of vanillin and vanillic acid was 583 mg l(-1). Further biotransformation was carried out using 0.5% (v/v) of isoeugenol under the resting cells conditions, yielding a vanillin concentration of 1.12 g l(-1) (molar yield 25.7%) after 60 h incubation. This study brings the first evidence for biotransformation of isoeugenol to vanillin and vanillic acid by a yeast strain.
从受污染水中分离出的假丝酵母（Candida galli）PGO6 菌株是第一株能够在异丁香酚生物转化过程中形成香草醛和香草酸的酵母菌株。通过薄层层析（TLC）、紫外吸收图谱的变化和高效液相色谱（HPLC）对产物进行了确认。表型和生理化学特性以及基于 ITS1-5.8S-ITS2 rDNA 区域扩增的分子系统发育分析表明，分离株 PGO6 被鉴定为假丝酵母（GenBank 登录号 HM641231）。从生长对数末期的 C. galli PGO6 静止细胞被用作异丁香酚生物转化的生物催化剂。在 30 小时的孵育中，使用 0.1%（v/v）异丁香酚和 6mg/ml 干重细胞，无需进一步优化，可获得 48%的香草醛（48%）和 19%的香草酸（19%）的最佳摩尔转化率。在这些条件下，香草醛和香草酸的总量为 583mg/L。在静止细胞条件下，进一步进行 0.5%（v/v）异丁香酚的生物转化，60 小时孵育后可得到 1.12g/L 的香草醛浓度（摩尔收率 25.7%）。本研究首次证明了酵母菌株能够将异丁香酚生物转化为香草醛和香草酸。
