Alternative Oils Tested as Feedstocks for Enzymatic FAMEs Synthesis: Toward a More Sustainable Process

Previously isolated and characterized Pseudomonas lipases were immobilized in a low-cost MP-1000 support by a re-loading procedure that allowed a high activity per weight of support. Immobilized LipA, LipC, and LipCmut lipases, and commercial Novozym® 435 were tested for fatty acid methyl ester (FAMEs) synthesis using conventional and alternative feedstocks. Triolein and degummed soybean oils were used as model substrates, whereas waste cooking oil and M. circinelloides oil were assayed as alternative, low cost feedstocks, whose free fatty acid (FFA), and acylglyceride profile was characterized. The reaction conditions for FAMEs synthesis were initially established using degummed soybean oil, setting up the best water and methanol concentrations for optimum conversion. These conditions were further applied to the alternative feedstocks and the four lipases. The results revealed that Pseudomonas lipases were unable to use the FFAs, displaying a moderate FAMEs synthesis, whereas a 44% FAMEs production was obtained when M. circinelloides oil was used as a substrate in the reaction catalysed by Novozym® 435, used under the conditions established for degummed soybean oil. However, when Novozym® 435 was tested under previously described optimal conditions for this lipase, promising values of 85 and 76% FAMEs synthesis were obtained for waste cooking oil and M. circinelloides oil, respectively, which might result in promising, nonfood, alternative feedstocks for enzymatic biodiesel production. © 2017 American Institute of Chemical Engineers Biotechnol. Prog., 33:1209-1217, 2017.