Presentation Information
[2BRBP-01-KL]Optimization of a surfactant-lipase complex for the transesterification of triolein and methanol
○Mervlyn Lalu Mohe1 (1. Doshisha University (Japan))
Keywords:
biodiesel; lipase; organic solvent; surfactant; transesterification
Optimization of a surfactant-lipase complex for the transesterification of triolein and methanol
Mervlyn Lalu Mohe, Yoshiro Tahara, and Michiaki Matsumoto
Department of Chemical Engineering and Materials Science, Doshisha University, Japan
Concerns about global warming and depleting petroleum reserves have led to the pursuit of biodegradable and sustainable combustibles. Developing renewable energy sources is crucial for sustainable human progress. Biodiesel has gained popularity as a carbon-neutral alternative to fossil fuels. Nevertheless, to adopt lipase-catalyzed biodiesel production in industry, several challenges must be overcome, including high costs, low operational stability in the presence of methanol and glycerol, easy product purification, and simple catalyst recovery. Since the solubility of lipase in both aqueous and organic solvents is quite low, solid-in-oil (S/O) nano-dispersion of a surfactant-lipase complex is beneficial for the production of methyl oleate (biodiesel). In the present study, to optimize the S/O nano-dispersion, the ratio of lipase surfactant, cyclohexane, and substrates was investigated.
The S/O nano-dispersion was prepared as described by Tahara et al.[1] Briefly, a water-in-oil emulsion containing lipase (from porcine pancreas free powder form) in water and sucrose erucate (ER-290) in cyclohexane was prepared and freeze-dried. The mixture of acetone and cyclohexane was added, and after overnight stirring, 1 mmol of triolein and 3 mmol of methanol per vial were added. Samples were taken at desired time intervals, centrifuged, and the supernatant was analyzed by HPLC-RID.
Different cyclohexane percentages were investigated, and result shows 5% more favorable. The utilization of organic solvents addresses two limitations: increasing the solubility of oil and methanol in the solvent and reducing the concentration of methanol surrounding the enzyme [2]. A higher amount of cyclohexane present in the reaction system could lead to dissolution of active sites and possible inhibition of lipase. Considering that organic solvents can hinder enzymatic synthesis by interacting directly with enzymes or diffusible substrates/products [3]. The surfactant-lipase ratio has been reported to significantly impact the production of surfactant-lipase complexes, protein recovery, and esterification yields [4]. 0.5 g and 1 g of ER-290 were chosen to coat different amounts of free lipase. From the results, 0.5 g shows superiority over 1 g of ER-290. This implies sufficiency to protect the organic solvent; however, 1 g of ER-290 could have completely blocked the lipase's active site from being accessed by the substrates. Additionally, 1 g of ER-290 provides a favorable reaction environment. Enzyme saturation from 50 mg to 100 mg of lipase occurs due to the excess amount of lipase present in the reaction system, thus rendering its active site inaccessible to substrates.
In conclusion, the effective S/O nano-dispersion exhibited three times the reaction rate of the control experiment. The amount of surfactant-lipase complex, cyclohexane, and substrates optimized is important for the transesterification of triolein and methanol.
[1] Tahara et al. (2008). Journal of Controlled Release, 131, 14–18
[2] Fu and Vasudevan. (2009). Energy & Fuels, 23, 4105-4111.
[3] Annapurna Devi et al. (2017). J Food Sci Technol, 54(9), 2871–2877.
[4] Annapurna Devi and Bhanu Radhika. (2018). Iran. J. Chem. Chem. Eng., 37 (4), 81-92.
Mervlyn Lalu Mohe, Yoshiro Tahara, and Michiaki Matsumoto
Department of Chemical Engineering and Materials Science, Doshisha University, Japan
Concerns about global warming and depleting petroleum reserves have led to the pursuit of biodegradable and sustainable combustibles. Developing renewable energy sources is crucial for sustainable human progress. Biodiesel has gained popularity as a carbon-neutral alternative to fossil fuels. Nevertheless, to adopt lipase-catalyzed biodiesel production in industry, several challenges must be overcome, including high costs, low operational stability in the presence of methanol and glycerol, easy product purification, and simple catalyst recovery. Since the solubility of lipase in both aqueous and organic solvents is quite low, solid-in-oil (S/O) nano-dispersion of a surfactant-lipase complex is beneficial for the production of methyl oleate (biodiesel). In the present study, to optimize the S/O nano-dispersion, the ratio of lipase surfactant, cyclohexane, and substrates was investigated.
The S/O nano-dispersion was prepared as described by Tahara et al.[1] Briefly, a water-in-oil emulsion containing lipase (from porcine pancreas free powder form) in water and sucrose erucate (ER-290) in cyclohexane was prepared and freeze-dried. The mixture of acetone and cyclohexane was added, and after overnight stirring, 1 mmol of triolein and 3 mmol of methanol per vial were added. Samples were taken at desired time intervals, centrifuged, and the supernatant was analyzed by HPLC-RID.
Different cyclohexane percentages were investigated, and result shows 5% more favorable. The utilization of organic solvents addresses two limitations: increasing the solubility of oil and methanol in the solvent and reducing the concentration of methanol surrounding the enzyme [2]. A higher amount of cyclohexane present in the reaction system could lead to dissolution of active sites and possible inhibition of lipase. Considering that organic solvents can hinder enzymatic synthesis by interacting directly with enzymes or diffusible substrates/products [3]. The surfactant-lipase ratio has been reported to significantly impact the production of surfactant-lipase complexes, protein recovery, and esterification yields [4]. 0.5 g and 1 g of ER-290 were chosen to coat different amounts of free lipase. From the results, 0.5 g shows superiority over 1 g of ER-290. This implies sufficiency to protect the organic solvent; however, 1 g of ER-290 could have completely blocked the lipase's active site from being accessed by the substrates. Additionally, 1 g of ER-290 provides a favorable reaction environment. Enzyme saturation from 50 mg to 100 mg of lipase occurs due to the excess amount of lipase present in the reaction system, thus rendering its active site inaccessible to substrates.
In conclusion, the effective S/O nano-dispersion exhibited three times the reaction rate of the control experiment. The amount of surfactant-lipase complex, cyclohexane, and substrates optimized is important for the transesterification of triolein and methanol.
[1] Tahara et al. (2008). Journal of Controlled Release, 131, 14–18
[2] Fu and Vasudevan. (2009). Energy & Fuels, 23, 4105-4111.
[3] Annapurna Devi et al. (2017). J Food Sci Technol, 54(9), 2871–2877.
[4] Annapurna Devi and Bhanu Radhika. (2018). Iran. J. Chem. Chem. Eng., 37 (4), 81-92.
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