Abstract
Due to the heterogeneity of oils, the use of mixtures of lipases with different activity for a large number of glycerol-linked carboxylic acids that compose the substrate has been proposed as a better alternative than the use of one specific lipase preparation in the enzymatic synthesis of biodiesel. In this work, mixtures of lipases from different sources were evaluated in their soluble form in the ethanolysis of soybean oil. A mixture of lipases (50% of each lipase, in activity basis) from porcine pancreas (PPL) and Thermomyces lanuginosus lipase (TLL) gave the highest fatty acid ethyl ester (FAEE) yield (around 20 wt.%), while the individual lipases gave FAEE yields 100 and 5 times lower, respectively. These lipases were immobilized individually by the cross-linked enzyme aggregates (CLEAs) technique, yielding biocatalysts with 89 and 119% of expressed activity, respectively. A mixture of these CLEAs (also 50% of each lipase, in activity basis) gave 90.4 wt.% FAEE yield, while using separately CLEAs of PPL and TLL, the FAEE yields were 84.7 and 75.6 wt.%, respectively, under the same reaction conditions. The mixture of CLEAs could be reused (five cycles of 6 h) in the ethanolysis of soybean oil in a vortex flow-type reactor yielding an FAEE yield higher than 80% of that of the first batch.
Highlights
Biodiesel is a promising substitute for petroleum-derived fuels [1,2,3,4,5,6]
Pseudomonas fluorescens lipase (PFL) with Candida Antarctica Lipase B (CALB) the yields were clearly worse using the mixture of lipases than the individual ones
A mixture of free lipases (PPL and Thermomyces lanuginosus lipase (TLL), 50/50 tributyrin activity ratio) showed a synergistic action in the rate of ethanolysis of soybean oil. Both lipases immobilized by the cross-linked enzyme aggregates (CLEAs) technique under their respective optimized protocols permitted to achieve high immobilization yields and recovered activities, but the protocols were quite different, avoiding the use of the enzymes co-immobilized in the same CLEA supramolecular structure
Summary
Its current production is manly carried out via alkaline transesterification of fatty acid-free oils and alcohols [7]. An alternative to the alkaline catalysts is the use of immobilized lipases [3,4,8,9,10,11], which allows the use of oils containing a high percentage of free fatty acids as raw material, because these enzymes can catalyze both transesterification and esterification reactions in media containing low water activity [8,12,13]. Several mixtures of lipases (mainly 1,3-especific and non-specific) have been reported as biocatalysts in biodiesel production, showing higher yields than those achieved using individual lipases [14,15,16,17,18,19,20,21], such as Lipozyme TL-IM. It has been shown that a mixture of the same lipase immobilized following different protocols (this may alter the lipase specificity [29]) improves the final biodiesel yields [30]
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
