Engineering School of Lorena, University of São Paulo, 116, Lorena, São Paulo 12602-810, Brazil.
Bioprocess Biosyst Eng. 2013 Apr;36(4):443-51. doi: 10.1007/s00449-012-0801-6. Epub 2012 Aug 18.
Optimal conditions for enzymatic synthesis of biodiesel from palm oil and ethanol were determined with lipase from Pseudomonas fluorescens immobilized on epoxy polysiloxane-polyvinyl alcohol hybrid composite under a microwave heating system. The main goal was to reduce the reaction time preliminarily established by a process of conventional heating. A full factorial design assessed the influence of ethanol-to-palm oil (8:1-16:1) molar ratio and temperature (43-57 °C) on the transesterification yield. Microwave irradiations varying from 8 to 15 W were set up according to reaction temperature. Under optimal conditions (8:1 ethanol-to-oil molar ratio at 43 °C), 97.56 % of the fatty acids present in the palm oil were converted into ethyl esters in a 12-h reaction, corresponding to a productivity of 64.2 mg ethyl esters g⁻¹ h⁻¹. This represents a sixfold increase from the process carried out under conventional heating, thus proving to be a potential tool for enhancing biochemical modification of oils and fats. In general, advantages of the new process include: (1) microwaves speed up the enzyme-catalyzed reactions; (2) there are no destructive effects on the enzyme properties, such as stability and substrate specificity, and (3) the microwave assistance allows the entire reaction volume to be heated uniformly. These bring benefits of a low energy demand and a faster conversion of palm oil into biodiesel.
采用固定化酶法，以荧光假单胞菌脂肪酶为催化剂，在微波加热体系中，以环氧聚硅氧烷-聚乙烯醇杂化复合材料为载体，对棕榈油与乙醇酶法合成生物柴油的最佳条件进行了研究。主要目的是在传统加热法初步确定的反应时间的基础上进一步缩短反应时间。采用全因子设计评估了乙醇与棕榈油摩尔比（8:1-16:1）和温度（43-57°C）对转酯化产率的影响。根据反应温度，设置了 8-15 W 的微波辐射。在最佳条件下（8:1 乙醇与油摩尔比，43°C），12 h 内棕榈油中 97.56%的脂肪酸转化为乙酯，产率为 64.2 mg 乙酯/g·h。与传统加热法相比，产率提高了 6 倍，证明这是一种增强油脂生化修饰的潜在工具。总的来说，新工艺具有以下优点：（1）微波能加速酶催化反应；（2）对酶的稳定性和底物特异性等性质没有破坏性影响；（3）微波辅助可使整个反应体积均匀加热。这带来了低能耗和更快将棕榈油转化为生物柴油的好处。
