Department of Chemistry, Institute of Chemical Technology, Matunga, Mumbai 400 019, India.
J Biotechnol. 2011 Oct 20;156(1):46-51. doi: 10.1016/j.jbiotec.2011.08.019. Epub 2011 Aug 23.
In present work, Rhizopus oryzae lipase immobilized on a film prepared using blend of hydroxylpropyl methyl cellulose (HPMC) and polyvinyl alcohol (PVA) was investigated for synthesis of citronellol esters with supercritical carbon dioxide (Sc-CO(2)) as a reaction medium. The transesterification reaction was optimized for various reaction parameters like effect of molar ratio, acyl donor, time, temperature, enzyme concentration, effect of pressure and co-solvent to achieve the maximum yield of desired product. The results obtained signify remarkable increment (about eightfold) in the yield of citronellol acetate (91%) as compared to that of free lipase (11%) in Sc-CO(2). The developed biocatalytic methodology provides a substantial advantage of low biocatalyst loading (1.5%, w/v), lower reaction temperature (45°C) and lower pressure (8 MPa) as compared to previous reports. The immobilization method has significantly enhanced the operational stability of lipase for ester synthesis under Sc-CO(2) conditions. The developed methodology was successfully applied for synthesis of three different industrially important citronellol esters namely citronellol acetate (91%), citronellol butyrate (98%), citronellol laurate (99%) with excellent yields using vinyl esters as acyl donor under Sc-CO(2) conditions. In addition, the immobilized biocatalyst was effectively recycled for three consecutive recycles.
在本工作中，研究了固定在羟丙基甲基纤维素（HPMC）和聚乙烯醇（PVA）混合物制备的薄膜上的米根霉脂肪酶，用于超临界二氧化碳（Sc-CO2）作为反应介质合成香茅醇酯。优化了各种反应参数，如摩尔比、酰基供体、时间、温度、酶浓度、压力和共溶剂的影响，以获得所需产物的最大产率。与游离脂肪酶（11%）相比，固定化酶在 Sc-CO2 中制备香茅醇乙酸酯（91%）的产率显著提高（约 8 倍）。与之前的报道相比，所开发的生物催化方法具有低生物催化剂用量（1.5%，w/v）、较低的反应温度（45°C）和较低的压力（8 MPa）的显著优势。固定化方法显著提高了脂肪酶在 Sc-CO2 条件下合成酯的操作稳定性。该方法在 Sc-CO2 条件下使用乙烯基酯作为酰基供体成功地用于合成三种不同的工业重要香茅醇酯，即香茅醇乙酸酯（91%）、香茅醇丁酸酯（98%）和香茅醇月桂酸酯（99%），产率很高。此外，固定化生物催化剂在三个连续循环中有效地回收。
