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

Cold active microbial lipases: Some hot issues and recent developments

Over the last decades, alginates, natural multifunctional polymers, have increasingly drawn attention as attractive compounds in the biomedical and pharmaceutical fields due to their unique physicochemical properties and versatile biological activities. The focus of the paper is to describe biological and pharmacological activity of alginates and to discuss the present use and future possibilities of alginates as a tool in drug formulation. The recent technological advancements with using alginates, issues related to alginates suitability as matrix for three-dimensional tissue cultures, adjuvants of antibiotics, and antiviral agents in cell transplantation in diabetes or neurodegenerative diseases treatment, and an update on the antimicrobial and antiviral therapy of the alginate based drugs are also highlighted.

/pdf/alginate-current-use-and-future-perspectives-in-5b9ql22d3j.pdf

Alginate: Current Use and Future Perspectives in Pharmaceutical and Biomedical Applications

Fatty acids methyl esters from vegetable oil by means of ultrasonic energy.

Regiospecificity is one of the major advantages of using lipase technology for the modification of oils and fats to produce high-value added products, such as cocoa butter equivalents, human milk fat substitutes, and other specific-structured lipids. Due to the high cost of biocatalysts, the mainstream applications of lipases for normal oils and fats are still limited. Therefore, positional specificity of lipases has the priority and will be the target property to be exploited for commercial and industrial developments, because no chemical method has such a specificity and is promising or possible for this task. In this paper, encouraging products resulting from this regiospecificity are reviewed together with the critical evaluation of their reaction schemes, side reactions and by-products, sources of substrate oils and acyl donors, and production processes.

Production of specific‐structured triacylglycerols by lipase‐catalyzed reactions: a review

Steryl esters of long-chain fatty acids have water-holding properties, and polyunsaturated fatty acids (PUFA) have various physiological functions. Because steryl ester of PUFA can be expected to have both features, we attempted to synthesize steryl esters of PUFA by enzymatic methods. Among lipases used, Pseudomonas lipase was the most effective for the synthesis of cholesteryl docosahexaenoate. When a mixture of cholesterol/docosahexaenoic acid (3:1, mol/mol), 30% water, and 3000 units/g of lipase was stirred at 40°C for 24 h, the esterification extent attained 89.5%. Under the same reaction conditions, cholesterol, cholestanol, and sitosterol were also esterified efficiently with docosahexaenoic, eicosapentaenoic, arachidonic, and γ-linolenic acids.

http://lib3.dss.go.th/fulltext/Journal/J.AOCS/J.AOCS/1999/no.6/jun1999,vol76,no6,p713-716.pdf

Enzymatic synthesis of steryl esters of polyunsaturated fatty acids

Ethyl docosahexaenoate (E-DHA) is efficiently enriched by the selective alcoholysis of ethyl esters originating from tuna oil with lauryl alcohol using immobilized lipase. Alcoholysis of ethyl esters by immobilized Rhizopus delemar lipase raised the E-DHA content in the unreacted ethyl ester fraction from 23 to 49 mol% in 90% yield. However, the content of ethyl eicosapentaenoate (E-EPA) was higher than the initial content. Hence we attempted to screen for a suitable lipase to decrease the E-EPA content, and chose Rhizomucor miehei lipase. Several factors affecting the alcoholysis of ethyl esters were investigated, and the reaction conditions were determined. When alcoholysis was performed at 30°C with shaking in a mixture containing ethyl esters/lauryl alcohol (1:3, mol/mol) and 4 wt% of the immobilized R. miehei lipase, the E-DHA content in the ethyl ester fraction was increased and the E-EPA content was decreased. By alcoholyzing ethyl esters in which the E-DHA content was 45 mol% (E-tuna-45) for 26 h, the E-DHA content was increased to 74 mol% in 71% yield and the E-EPA content was decreased from 12 to 6.2 mol%. To investigate the stability of the immobilized lipase, batch reactions were carried out continually by replacing the reaction mixture with fresh E-tuna-45/lauryl alcohol (1:3, mol/mol) every 24 h. The decrease in the alcoholysis extent was only 17% even after 100 cycles of reaction. It was found that increasing the proportion of lauryl alcohol increased the conversion of E-EPA to lauryl-EPA. When an ethyl ester mixture in which the E-DHA content was 60 mol% (E-tuna-60) was alcoholyzed for 24 h with 7 molar equivalents of lauryl alcohol, the E-DHA content was raised to 93 mol% with 74% yield and the E-EPA content was reduced from 8.6 to 2.9 mol%.

Purification of ethyl docosahexaenoate by selective alcoholysis of fatty acid ethyl esters with immobilized Rhizomucor miehei lipase.

l-Menthol has been widely used as a food additive and an ingredient of cosmetics, and it is esterified to moderate the strong flavor. We attempted esterification of l-menthol with long-chain unsaturated fatty acid in an organic solvent-free enzymatic system. Commercially available lipases were screened, and Candida rugosa lipase was selected as a catalyst. Several factors affecting the esterification were investigated, and the reaction conditions were determined as follows: A reaction mixture of l-menthol/fatty acid (1:3, mol/mol), 30% water, and 700 units of the lipase per gram of reaction mixture was incubated at 30°C with stirring. After 24 h under these conditions, the esterification extents of l-menthol with oleic, linoleic, and α-linolenic acids reached 96, 88, and 95%, respectively. The structure of the esterified product was confirmed by mass, infrared, and nuclear magnetic resonance spectroscopies. Bacause Candida lipase acted strongly on l-menthol and very weakly on d-menthol, dl-menthol was esterified with oleic acid under the same conditions. The reaction showed high enantioselectivity; the enantiomeric ratio (E) was 31, and enantiomeric excess (ee) of l-menthyl oleate reached 88% after 32 h.

Enzymatic synthesis of l-menthyl esters in organic solvent-free system

Ethyl esterification of docosahexaenoic acid in an organic solvent-free system with immobilized Candida antarctica lipase.

Sodium alginate oligosaccharides (NaAOs) consisting of a mixture of eight oligosaccharides have previously been reported to lower blood pressure. We investigated in this study the excretion of NaAOs into the urine or feces, and attempted to elucidate the mechanism for lowering blood pressure by using isolated mesenteric arteries from the rabbit. The recovery rate of P8, which is the main component of NaAOs, was 5.2% and 58.9% over 48 hours in the urine and feces, respectively. The mechanism for lowering blood pressure appeared to be NaAOs having calcium antagonist activity, especially voltage-operated calcium channels. Our results suggest that NaAOs are substantially excreted into the feces, although some of them may be absorbed internally, exerting antagonist activity towards the calcium channels, especially voltage-operated calcium channels.

https://www.tandfonline.com/doi/pdf/10.1271/bbb.60620

Takashi Baba

Papers

Enzymatic synthesis of steryl esters of polyunsaturated fatty acids

Purification of ethyl docosahexaenoate by selective alcoholysis of fatty acid ethyl esters with immobilized Rhizomucor miehei lipase.

Enzymatic synthesis of l-menthyl esters in organic solvent-free system

Ethyl esterification of docosahexaenoic acid in an organic solvent-free system with immobilized Candida antarctica lipase.

Metabolism and Calcium Antagonism of Sodium Alginate Oligosaccharides