Biodiesel production catalyzed by immobilized lipases offers the possibility of easy reuse of the catalyst, which is very important to minimize costs and to make this process economically feasible. In this study, the reuse of three commercial immobilized lipases (Novozym 435, Lipozyme RM IM, and Lipozyme TL IM) was investigated in ethanolysis of soybean oil. The effect of the use of solvents (ethanol, butanol, and hexane) to wash the immobilized lipases before the enzyme reuse was evaluated, as well as the lipase reuse without solvent washing. The washing with butanol and ethanol led to the lowest decrease in ester yield after the first batch and allowed the highest glycerol removal (>85 %) from biocatalysts. The biocatalysts were incubated at 50 °C for 2 h in these three solvents. Esterification activities of the enzyme preparations, scanning electron microscopy (SEM) analyses of the beads, and protein content in organic phase were evaluated before and after incubation in the solvent. SEM analysis showed a significant change in beads morphology of Novozym 435 after contact with hexane. For Lipozyme TL IM lipase, this effect was visualized with ethanol.
The conventional biodiesel production process has some disadvantages. It is necessary to use refined vegetable oils with low free fatty acids (FFAs) content. An alternative route is to use low-cost acid oils in an enzymatic process. The use of lipases allows simultaneous esterification of FFAs and transesterification of triglycerides present in raw material forming alkyl esters. The aim of this work was to study the production of biodiesel using soybean oils with different acid contents (Acid Value of 8.5, 50, 90) and ethanol catalyzed by commercial immobilized lipases (Novozym 435, Lipozyme RM IM and Lipozyme TL IM). A significant decrease of acid value was observed mainly with Novozym 435 and Lipozyme RM IM. The use of a mixture of two immobilized lipases was also investigated to decrease catalyst cost and increase the amount of ester produced. The three commercial immobilized lipases were mixed in a dual system and tested for biodiesel synthesis from acid oil (AV of 8.5, 50 and 90). A positive synergistic effect occurred mainly for Lipozyme TL IM (1,3-specific lipase) and Novozym 435 (non-specific lipase) blend. The ester content doubled when this lipase mixture was used in ethanolysis of acid oil with AV of 90.
RESUMO -Biodiesel é um biocombustível obtido a partir da reação de transesterificação de óleos vegetais com alcoóis de cadeia curta, que pode ser catalisada por lipases imobilizadas. Para diminuir o custo do processo, o biocatalisador pode ser recuperado, lavado com solvente e reutilizado. Assim, foram avaliados os efeitos do solvente (etanol, n-butanol e n-hexano) em três lipases comerciais imobilizadas (Novozym 435, Lipozyme RM IM, Lipozyme TL IM). Os biocatalisadores foram incubados nos solventes por 2 h a 50 ºC. A suspensão foi centrifugada e com o sobrenadante foi realizada a análise do teor de proteínas. A atividade de esterificação da preparação enzimática, bem como a análise de Microscopia Eletrônica de Varredura, antes e após incubação no solvente foram determinadas. A análise por MEV mostrou uma alteração significativa da estrutura da Novozym 435 após incubação em n-hexano, enquanto que para a lipase Lipozyme TL IM, esse efeito foi visualizado, principalmente, com etanol.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.