A review on biodiesel production using catalyzed transesterification

Biodiesel fuel production by transesterification of oils.

Industrial applications of microbial lipases

https://seniordesign.engr.uidaho.edu/2007_2008/frenchfryfuel/Biodiesel%20from%20WVO%20Part%201.pdf

Biodiesel production from waste cooking oil: 1. Process design and technological assessment

https://www.massey.ac.nz/%7Eychisti/Lipases.pdf

Production, purification, characterization, and applications of lipases.

Biodiesel fuel (fatty acid methyl esters; FAMEs) can be produced by methanolysis of waste edible oil with a lipase. The degree of methanolysis was low in reaction systems so far reported, and the lipase catalyst could not be reused in spite of using immobilized enzyme. We clarified this problem was due to the irreversible inactivation of the lipase by contact with insoluble methanol (MeOH). Based on this result, we developed a stepwise methanolysis system with immobilized Candida antarctica lipase. Two-step batch methanolysis was most effective for the production of biodiesel fuel from waste oil: the first-step reaction was conducted in the presence of 1/3 molar equivalent of MeOH for the stoichiometric amount, and the second-step reaction was performed by adding 2/3 molar equivalent of MeOH. If the immobilized carrier is destroyed by agitation in a reactor with impeller, three-step flow reaction will be available: the first-step substrates were waste oil and 1/3 molar equivalent of MeOH; the second-step, the first-step eluate and 1/3 molar equivalent of MeOH; the third-step, the second-step eluate and 1/3 molar equivalent of MeOH. The conversion of waste oil to biodiesel fuel reached >90% in the two reaction systems, and the lipase catalyst could be used for >100 days without decrease of the activity. The stepwise alcoholysis could successfully be applied to ethanolysis of tuna oil.

Enzymatic alcoholysis for biodiesel fuel production and application of the reaction to oil processing

Crude soybean oil did not undergo methanolysis with immobilized Candida antarctica lipase but degummed oil did. Therefore, the substance that was removed in the degumming step was estimated to inhibit the methanolysis of soybean triacylglycerols (TAGs). The main components of soybean gum are phospholipids (PLs), and soybean PLs actually inhibited the methanolysis reaction. In addition, PLs were detected in chloroform/methanol (MeOH) extracts from the immobilized lipase preparation that had been used in the methanolysis of crude soybean oil. These results showed that PLs were at least one of the inhibitory substances in methanolysis of TAGs. The inhibition may due to the interference of the interaction of the lipase molecule with substrates by PLs bound on immobilized preparation. These findings indicated that degummed oil has to be used as a substrate for enzymatic methanolysis. Indeed, three-step methanolysis successfully converted 93.8% degummed soybean oil to its corresponding methyl esters, and the lipase could be reused for 25 cycles without any loss of the activity.

Conversion of degummed soybean oil to biodiesel fuel with immobilized Candida antarctica lipase

The conversion of waste edible oil to biodiesel fuel in a fixed-bed bioreactor was investigated. Three-step methanolysis of waste oil was conducted using three columns packed with 3 g of immobilized Candida antarctica lipase. A mixture of waste oil and 1/3 molar equivalent of methanol against total fatty acids in the oil was used as substrate for the first-step reaction, and mixtures of the first- and second-step eluates and 1/3 molar equivalent of methanol were used for the second- and third-step reactions, respectively. Ninety percent of waste oil was converted to the corresponding methyl esters (ME) by feeding substrate mixtures into the first, second, and third reactors at flow rates of 6, 6 and 4 mL/h, respectively. We also attempted one-step methanolysis of waste oil. When a mixture of waste oil and 90% ME-containing eluate (1∶3, wt/wt) and an equimolar amount of methanol against total fatty acids in the waste oil was fed into a reactor packed with 3 g of immobilized C. antarctica lipase at a flow rate of 4 mL/h, the ME content in the eluate reached 90%. The immobilized biocatalyst could be used for 100 d in the two reaction systems without significant decrease in its activity. Waste oil contained 1980 ppm water and 2.5% free fatty acids, but these contaminants had little influence on enzymatic production of biodiesel fuel.

Enzymatic conversion of waste edible oil to biodiesel fuel in a fixed-bed bioreactor

Three lipases, isolated previously in our laboratory, each with different fatty acid and positional specificities, and a known lipase fromCandida cylindracea were screened for concentrating docosahexaenoic (DHA) and eicosapentaenoic (EPA) acids in glycerides.Geotrichum candidum lipase was found to be suitable for their concentration in glycerides. Tuna oil was treated at 30°C with this lipase for 16 h, and 33.5% hydrolysis resulted in the production of glycerides containing 48.7% of DHA and EPA. The hydrolysis was not increased despite adding further lipase, so the glycerides were extracted, and the reaction was repeated. The second hydrolysis produced glycerides containing 57.5% of DHA and EPA in a 54.5% yield, with recovery of 81.5% of initial DHA and EPA. Of the total glycerides, 85.5% were triglycerides. These results showed thatG. candidum lipase was effective in producing glycerides that contained a high concentration of polyunsaturated fatty acids in good yield.

Enrichment of polyunsaturated fatty acids withGeotrichum candidum lipase

To purify docosahexaenoic acid (DHA), we attempted the selective esterification of fatty acids originating from tuna oil with lipases. Tuna oil was hydrolyzed in NaOH-ethanol solution, and the resulting fatty acid mixture [DHA, 23.2%; named tuna-free fatty acid (FFA)] was used as a starting material. Rhizopus delemar which acted lightly on DHA, was a suitable catalyst for the selective esterification of tuna-FFA, and lauryl alcohol was the best substrate. The reaction proceeded most effectively when a mixture of 2.4 g lauryl alcohol/tuna-FFA (2:1, mol/mol), 0.6 g water, and 600 U Rhizopus lipase was incubated at 30°C for 20 h with stirring at 500 rpm. Under these conditions 72% of tuna-FFA was esterified, and 84% of DHA was recovered in the unesterified fatty acid fraction. The DHA content in the fatty acid fraction rose from 23 to 73% with this reaction. To further elevate the DHA content, the unesterified fatty acids were extracted, and then esterified again under the same conditions. By this repeated esterification, DHA was purified to 89% with a recovery of 71% of its initial content.

Yuji Shimada

Papers

Enzymatic alcoholysis for biodiesel fuel production and application of the reaction to oil processing

Conversion of degummed soybean oil to biodiesel fuel with immobilized Candida antarctica lipase

Enzymatic conversion of waste edible oil to biodiesel fuel in a fixed-bed bioreactor

Enrichment of polyunsaturated fatty acids withGeotrichum candidum lipase

Purification of docosahexaenoic acid by selective esterification of fatty acids from tuna oil with Rhizopus delemar lipase