Sharma Shivika, Kanwar Kriti, Kanwar Shamsher S
Department of Biotechnology, Himachal Pradesh University, Summer Hill, Shimla, 171 005, India.
3 Biotech. 2016 Dec;6(2):183. doi: 10.1007/s13205-016-0486-7. Epub 2016 Aug 27.
Ascorbyl palmitate was synthesized using a Celite-immobilized commercial lipase (Lipolase 100L) in dimethylsulfoxide (DMSO) as an organic solvent system. Lipase immobilized by surface adsorption onto Celite 545 matrix and subsequently exposed to 1 % glutaraldehyde showed 75 % binding of protein. The Celite-bound lipase was optimally active at 75 °C and pH 8.5 under shaking and showed maximum hydrolytic activity toward p-NPP as a substrate. The bound lipase was found to be stimulated only in the presence of Al and EDTA. All surfactants (Tween-20, Tween-80 and Triton X-100) had an inhibitory effect on lipase activity. The optimization of various reaction conditions of ascorbyl palmitate was achieved considering one factor at a time. The esterification of ascorbic acid and palmitic acid was carried out with 1 M ascorbic acid and 2.5 M palmitic acid in DMSO at 75 °C for 18 h under shaking (120 rpm). Molecular sieves had an important effect on the ester synthesis resulting in an enhanced yield. The by-product (HO) produced in the reaction was scavenged by the molecular sieves (20 mg/ml) added in the reaction mixture which enhanced the ester yield to 80 %. The characterization of synthesized ester was done through FTIR spectroscopy.
抗坏血酸棕榈酸酯是在二甲基亚砜（DMSO）作为有机溶剂体系中，使用硅藻土固定化的商业脂肪酶（Lipolase 100L）合成的。通过表面吸附固定在硅藻土545基质上并随后暴露于1%戊二醛的脂肪酶显示出75%的蛋白质结合率。结合在硅藻土上的脂肪酶在75℃和pH 8.5下振荡时具有最佳活性，并且对以对硝基苯磷酸酯（p-NPP）为底物表现出最大水解活性。发现结合的脂肪酶仅在铝（Al）和乙二胺四乙酸（EDTA）存在时受到刺激。所有表面活性剂（吐温-20、吐温-80和曲拉通X-100）对脂肪酶活性都有抑制作用。一次考虑一个因素实现了抗坏血酸棕榈酸酯各种反应条件的优化。在DMSO中，用1 M抗坏血酸和2.5 M棕榈酸在75℃下振荡（120转/分钟）18小时进行抗坏血酸和棕榈酸的酯化反应。分子筛对酯合成有重要影响，导致产率提高。反应中产生的副产物（HO）被添加到反应混合物中的分子筛（20毫克/毫升）清除，这使酯产率提高到80%。合成酯的表征通过傅里叶变换红外光谱（FTIR）进行。
