Department of Chemistry, Wroclaw University of Environmental and Life Sciences, Norwida 25, 50-375, Wrocław, Poland.
Dipartimento di Chimica, Materiali ed Ingegneria Chimica "Giulio Natta" Politecnico di Milano, Via Mancinelli 7, 20131, Milan, Italy.
Sci Rep. 2021 Sep 22;11(1):18794. doi: 10.1038/s41598-021-97585-w.
The demand for natural food flavorings increases every year. Biotransformation has become an attractive approach to obtain natural products. In this work, enantiomerically pure (R)-(+)-δ-decalactone was obtained by reduction of the C=C double bond of natural massoia lactone in a continuous-flow reactor. Of 13 different ene-reductases isolated, purified and tested, OYE3 was found to be the most efficient biocatalyst. The selected biocatalyst, either in the form of purified enzyme, cell lysate, whole cells or immobilized cells, was tested in the batch system as well as in the packed-bed flow bioreactor. The biotransformation performed in batch mode, using Ca-alginate immobilized cells of Escherichia coli BL21(DE3)/pET30a-OYE3, furnished the desired product with complete conversion in 30 min. The process was intensified using a continuous-flow reactor-membrane filtration system (flow 0.1 mL/min, substrate concentration 10 mM, pH 7, 24 °C) with cell lysate as biocatalyst combined with a cofactor regeneration system, which allowed obtaining > 99% bioconversion of massoia lactone.
天然食品调味剂的需求逐年增加。生物转化已成为获得天然产物的一种有吸引力的方法。在这项工作中，通过在连续流反应器中还原天然芒果内酯的 C=C 双键，得到了对映体纯的（R）-（+）-δ-癸内酯。在分离、纯化和测试的 13 种不同的烯还原酶中，发现 OYE3 是最有效的生物催化剂。无论是以纯化酶、细胞裂解物、全细胞还是固定化细胞的形式，所选的生物催化剂都在分批系统和填充床流动生物反应器中进行了测试。在分批模式下进行的生物转化，使用 Ca-海藻酸钠固定化大肠杆菌 BL21(DE3)/pET30a-OYE3 细胞，在 30 分钟内完成了所需产物的完全转化。该过程通过连续流反应器-膜过滤系统（流速 0.1 mL/min、底物浓度 10 mM、pH 7、24°C）进行强化，使用细胞裂解物作为生物催化剂，并结合辅因子再生系统，允许获得芒果内酯的>99%的生物转化率。
