Kiran K R, Divakar S
Fermentation Technology and Bioengineering, Central Food Technological Research Institute, Mysore-570 013, India.
J Biotechnol. 2001 May 4;87(2):109-21. doi: 10.1016/s0168-1656(01)00242-5.
Lipases from Rhizomucor miehei (Lipozyme IM20) and porcine pancreas (PPL) were employed as catalysts for the esterification reaction between the hydroxyl group of lactic acid and the carboxyl group of organic acids. Reactions were carried out at both shake-flask and bench-scale levels. Various parameters, such as solvent, temperature, substrate and enzyme concentrations, effect of buffer volume, buffer pH and water volume, were investigated for optimization of yields. While ethylmethyl ketone (EMK) was found to be the best solvent for shake-flask reactions, chloroform gave higher yields at bench-scale level. Detailed studies were carried out with respect to the synthesis of palmitoyl and stearoyl lactic acids. At shake-flask level, maximum yields of 37.5 and 40% were observed in case of palmitoyl and stearoyl lactic acids, respectively, with Lipozyme IM20; at bench-scale level, the maximum yields were 85.1 and 99% respectively, when PPL was employed. Of all the organic acids employed (C(2)--C(18)), only lauric, palmitic and stearic acids gave yields above 50%. At bench-scale level, PPL could be reused for up to three cycles with yields above 40%. Esters prepared were found to conform to Food Chemical Codex (FCC) specifications in terms of acid value, ester value, sodium and lactic acid contents.
米黑根毛霉脂肪酶（Lipozyme IM20）和猪胰脂肪酶（PPL）被用作乳酸羟基与有机酸羧基之间酯化反应的催化剂。反应在摇瓶和实验室规模下进行。研究了各种参数，如溶剂、温度、底物和酶浓度、缓冲液体积、缓冲液pH值和水量的影响，以优化产率。虽然发现甲乙酮（EMK）是摇瓶反应的最佳溶剂，但在实验室规模下，氯仿的产率更高。针对棕榈酰乳酸和硬脂酰乳酸的合成进行了详细研究。在摇瓶水平下，使用Lipozyme IM20时，棕榈酰乳酸和硬脂酰乳酸的最大产率分别为37.5%和40%；在实验室规模下，使用PPL时，最大产率分别为85.1%和99%。在所使用的所有有机酸（C(2)-C(18)）中，只有月桂酸、棕榈酸和硬脂酸的产率高于50%。在实验室规模下，PPL可以重复使用多达三个循环，产率高于40%。所制备的酯在酸值、酯值、钠和乳酸含量方面符合食品化学法典（FCC）规范。
