This is the first report on morphologically different strains of cyanobacteria: Arthrospira maxima, Nostoc cf-muscorum and Nodularia sphaerocarpa used for enantioselective bioreduction of selected, structurally different diethyl esters of oxophosphonic acids. The efficiency of the asymmetric hydrogen transfer was strongly dependent on the chemical structure of the substrates. Arthrospira maxima was active only toward diethyl (S)-2-oxopropylphosphonate (20% of yield, 99% of ee), whereas the application of Nostoc cf-muscorum as a biocatalyst allowed diethyl (S)-2-hydroxy-2-phenylethylphosphonate with a high enantiomeric excess (99%) and with 26% conversion degree to be obtained. Employing Nodularia sphaerocarpa led to the most spectacular result – diethyl (S)-2-hydroxy-2-phenylethylphosphonate with a degree of conversion of 99% and an optical purity of 92%. Enantioselective bioconversion of oxophosphonate with an aromatic side group located in the immediate vicinity of the carbonyl functionality was achieved for the first time. Additionally, flow cytometry showed excellent resistance of the cells of Nodularia sphaerocarpa against the examined xenobiotic – 2-oxo-2-phenylethylphosphonate, these cells remain viable at the concentration of 10 mM of the bioconversion substrate compared to the 1 mM described previously for a fungal biocatalyst. The effect of cultivation medium, light source and light cycle (light : dark) on the effectiveness of the biotransformation process was examined.
这是一份关于形态上不同的蓝藻菌株的首次报告:阿尔特罗
螺旋藻(Arthrospira maxima)、拟氮球藻(Nostoc cf-muscorum)和球形小结藻(Nodularia sphaerocarpa),它们用于选择性、结构不同的
二乙基氧
膦酸酯的对映选择性
生物还原。非对称氢转移的效率在很大程度上依赖于底物的
化学结构。阿尔特罗
螺旋藻仅对
二乙基(S)-2-氧
丙基膦酸酯表现出活性(产率20%,对映体过量99%),而采用拟氮球藻作为
生物催化剂能够得到具有高对映选择过量(99%)和26%转化率的
二乙基(S)-2-羟基-2-苯
乙基膦酸酯。使用球形小结藻的结果最为显著——可获得转化率为99%且光学纯度为92%的
二乙基(S)-2-羟基-2-苯
乙基膦酸酯。首次实现了带有芳香侧基的氧
膦酸酯在羰基功能团附近的对映选择性
生物转化。此外,流式细胞术显示球形小结藻细胞对所测定的外源物质——2-氧-2-苯
乙基膦酸酯具有极好的耐受性,这些细胞在10 mM的
生物转化底物浓度下仍保持活力,而之前针对真菌
生物催化剂仅为1 mM。研究还考察了
培养基、光源和光周期(光:暗)对
生物转化过程有效性的影响。