Increase in volume of biodiesel production in the world scenario proves that biodiesel is accepted as an alternative to conventional fuel. Production of biodiesel using alkaline catalyst has been commercially implemented due to its high conversion and low production time. For the product and process development of biodiesel, enzymatic transesterification has been suggested to produce a high purity product with an economic, environment friendly process at mild reaction conditions. The enzyme cost being the main hurdle can be overcome by immobilization. Immobilized enzyme, which has been successfully used in various fields over the soluble counterpart, could be employed in biodiesel production with the aim of reducing the production cost by reusing the enzyme. This review attempts to provide an updated compilation of the studies reported on biodiesel production by using lipase immobilized through various techniques and the parameters, which affect their functionality.

Production of Biodiesel Using Immobilized Lipase—A Critical Review

Lipases are a group of enzymes naturally endowed with the property of performing reactions in aqueous as well as organic solvents. The esterification reactions using lipase(s) could be performed in water-restricted organic media as organic solvent(s) not only improve(s) the solubility of substrate and reactant in reaction mixture but also permit(s) the reaction in the reverse direction, and often it is easy to recover the product in organic phase in two-phase equilibrium systems. The use of organic solvent tolerant lipase in organic media has exhibited many advantages: increased activity and stability, regiospecificity and stereoselectivity, higher solubility of substrate, ease of products recovery, and ability to shift the reaction equilibrium toward synthetic direction. Therefore the search for organic solvent tolerant enzymes has been an extensive area of research. A variety of fatty acid esters are now being produced commercially using immobilized lipase in nonaqueous solvents. This review describes the organic tolerance and industrial application of lipases. The main emphasis is to study the nature of organic solvent tolerant lipases. Also, the potential industrial applications that make lipases the biocatalysts of choice for the present and future have been presented.

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Organic solvent tolerant lipases and applications.

Understanding Candida rugosa lipases: an overview.

Lipases are versatile catalysts. In addition to their natural reaction of fat hydrolysis, lipases catalyze a plethora of other reactions such as esterification, amidation, and transesterification of esters as well as organic carbonates. Moreover, lipases accept a wide variety of substrates while maintaining their regioselectivity and stereoselectivity. Lipases are highly stable even under adverse conditions such as organic solvents, high temperatures, and so forth. Applications of lipases include production of food additives, chiral intermediates, and pharmaceutical products. Among these, synthesis of various chiral intermediates in pharmaceutical industry and cocoa butter substitutes is being commercially exploited currently. Lipase-catalyzed esterification and transesterification in anhydrous media (e.g., organic solvents and supercritical fluids) has been an area of major research activity in the past decade or so. Absence of water eliminates the competing hydrolysis reaction. Moreover, substrate speci...

Lipase-Catalyzed Esterification

Wastewater generated from fresh, vegetables and meat shops contains high concentrations of nutrients, COD, BOD and TSS. Therefore, the direct discharge of wet market wastewater into natural water may increase the pollution level. Wet market wastewater is rich with nutrients necessary for microalgae growth. Therefore, it represent a superlative environment for producing high quantity of microalgae biomass which have several applications in aquaculture, human nutrition and pharmaceutical industries. Phycoremediation is a process with high potential for the treatment wastewater and removal of nutrients and heavy metals as well as the production of microalgae biomass. However, the main challenges for the phycoremediation technology lie in the wastewater composition, microalgae species, and the competition process between the microalgae strain and the indigenous organisms as well as final utilization of biomass yield. The present review discusses the dual roles of phycoremediation for nutrients and heavy metals removal and microalgae biomass production. The microbiological aspects of phycoremediation, mechanism for heavy metals removal from wastewater, as well as factors affecting wastewater treatment are reviewed. It appears that phycoremediation plays an important role in the treatment of wastewater and production of microalgae biomass.

The dual roles of phycoremediation of wet market wastewater for nutrients and heavy metals removal and microalgae biomass production

Following a simple and quick treatment based on dissolving the crude lipase from Candida rugosa in different percentages (v/v) of several polar organic solvents (methanol, ethanol, 1 and 2-propanol, 1 and 2-butanol and acetone) followed by dialysis, different preparations with enhanced activities were obtained. The opening of the lid covering the active site is proposed as the reason for explaining the activity enhancement, both in aqueous and anhydrous organic media.

Treatment of Candida Rugosa Lipase with Short-Chain Polar Organic Solvents Enhances its Hydrolytic and Synthetic Activities

Two methodologies have been carried out on the lipase from Candida rugosa, ammonium sulphate precipitation and solubilization with several organic solvents, obtaining preparations with enhanced activities compared to the crude enzyme. We have employed them in two biotransformation reactions obtaining again enhanced activities compared to the native enzyme.

S. Chamorro

Papers

Treatment of Candida Rugosa Lipase with Short-Chain Polar Organic Solvents Enhances its Hydrolytic and Synthetic Activities

Biotransformations catalyzed by Candida rugosa lipase partially purified by precipitation and by organic solvents treatment