Lipase catalysed hydrolysis of ricebran oil by free and immobilised enzyme system in batch stirred reactor

Lipase applications in oil hydrolysis with a case study on castor oil: a review

Abstract: Lipase (triacylglycerol acylhydrolase) is a unique enzyme which can catalyze various types of reactions such as hydrolysis, esterification, alcoholysis etc. In particular, hydrolysis of vegetable oil with lipase as a catalyst is widely studied. Free lipase, lipase immobilized on suitable support, lipase encapsulated in a reverse micelle and lipase immobilized on a suitable membrane to be used in membrane reactor are the most common ways of employing lipase in oil hydrolysis. Castor oil is a unique vegetable oil as it contains high amounts (90%) of a hydroxy monounsaturated fatty acid named ricinoleic acid. This industrially important acid can be obtained by hydrolysis of castor oil. Different conventional hydrolysis processes have certain disadvantages which can be avoided by a lipase-catalyzed process. The degree of hydrolysis varies widely for different lipases depending on the operating range of process variables such as temperature, pH and enzyme loading. Immobilization of lipase on a suitable support can enhance hydrolysis by suppressing thermal inactivation and estolide formation. The presence of metal ions also affects lipase-catalyzed hydrolysis of castor oil. Even a particular ion has different effects on the activity of different lipases. Hydrophobic organic solvents perform better than hydrophilic solvents during the reaction. Sonication considerably increases hydrolysis in case of lipolase. The effects of additives on the same lipase vary with their types. Nonionic surfactants enhance hydrolysis whereas cationic and anionic surfactants decrease it. A single variable optimization method is used to obtain optimum conditions. In order to eliminate its disadvantages, a statistical optimization method is used in recent studies. Statistical optimization shows that interactions between any two of the following pH, enzyme concentration and buffer concentration become significant in presence of a nonionic surfactant named Span 80.

Hydrolysis of rice bran oil using immobilized lipase in a stirred batch reactor

Abstract: Candida cylindracea lipase was immobilized by adsorption on acid washed glass beads. It was observed that protein loading of the support depends on the size of the particle, with smaller particle containing higher amount of protein per unit weight. Initial reaction rate linearly varied up to enzyme concentration of 17.25 U/mL. Amount of free fatty acids produced was linearly proportional up to the enzyme loading of 1650 μg/g of bead. Achievement of chemical equilibrium took longer time in the case of less protein loading. Degree of hydrolysis was found to decrease in second and third consecutive batch operations on repeated use of immobilized lipase.

Kinetics of enzymatic hydrolysis of rice bran oil in organic system

Abstract: The kinetics of enzymatic hydrolysis of rice bran oil in organic solvent ( n -hexane) by free and immobilized Candida lipolytica lipase were investigated in a batch reactor. The n -hexane does not alter pH and temperature optima, but an increase in n -hexane concentration decreases the enzyme activity. The kinetic model proposed to describe the inhibitory effect of solvents on lipolysis was found to fit our data well.

Biochemical engineering fundamentals

Abstract: Biochemical Engineering Fundamentals, 2/e, combines contemporary engineering science with relevant biological concepts in a comprehensive introduction to biochemical engineering. The biological background provided enables students to comprehend the major problems in biochemical engineering and formulate effective solutions.

A simple and rapid colorimetric method for determination of free fatty acids for lipase assay

Abstract: A simple and rapid colorimetric method was developed to determine the lipase activity for fat splitting Free fatty acids produced by lipase from triacylglycerols were determined by observing the color developed using cupric acetate-pyridine as a color developing reagent This modified method requires only a few minutes to determine the free fatty acids, whereas it takes over 20 min by the conventional methods which require solvent evaporation and centrifugation steps The sensitivity and reproducibility of the method were good for caproic, caprylic, capric, lauric, myristic, palmitic, stearic and oleic acids

Characteristics of lipase‐catalyzed hydrolysis of olive oil in AOT–isooctane reversed micelles

Abstract: Candida rugosa lipase solubilized in organic solvents in the presence of both surfactant and water could catalyze the hydrolysis of triglycerides, and kinetic analysis of the lipase-catalyzed reaction was found to be possible in this system. Among eight organic solvents tested, isooctane was most effective for the hydrolysis of olive oil in reversed micelles. Temperature effect, pH profile, K(m,app) and V(max,app) were determined. Among various chemical compounds, Cu(2+), Hg(2+), and Fe(3+) inhibited lipase severely. But the enzyme activity was restorable partially by adding histidine or glycine to the system containing these metal ions. The enzyme activity was dependent on R (molar ratio of water to surfactant) and maximum activity was obtained at R = 10.5. Upon addition of glycerol to the reversed micelles, lipase activity was affected in a different fashion depending on the R values. Stability of the lipase in reversed micelles was also dependent on R, and it was most stable at R = 5.5.

Continuous hydrolysis of olive oil by lipase in microporous hydrophobic membrane bioreactor

Abstract: Continuous hydrolysis of olive oil byCandida cylindracea’s lipase was studied in a microporous hydrophobic membrane bioreactor. Olive oil and buffer solution, fed continuously through two compartments partitioned by membrane, caused reaction at the interface of lipase-adsorbed membrane and buffer solution. Fatty acid was obtained in a single phase without being mixed with components of other phases. At all mean residence times, countercurrent flow mode was superior to cocurrent one. The lipase was adsorbed onto the membrane, and its adsorption was suggested to be partially specific from the experiments with enzymes having various levels of purity. The percent hydrolysis depended hyperbolically on the interfacial enzyme concentration. The hydrolysis seemed to be limited by diffusion of fat or fatty acid through the micropores of the membrane at higher interfacial enzyme concentrations. The lipase was stabilized significantly by glycerol added to the buffer solution. Satisfactory performance of the membrane bioreactor was obtained in a longterm continuous operation which lasted for 24 days by feeding buffer-glycerol (18.0%) solution over the adsorbed lipase. The operational half-life of the adsorbed enzyme was 15 days at 40 C.

Application of immobilized lipase to hydrolysis of triacylglyceride

Abstract: Lipase from Candida cylindracea was immobilized by entrapment with photo-crosslinkable resin prepolymers or urethane prepolymers, and by covalent binding or by adsorption to different types of porous inorganic or organic supports. All of the immobilized lipase preparations thus obtained showed some activity for hydrolysis of olive oil. Lipase entrapped with a hydrophobic photo-cross-linkable resin prepolymer exhibited the highest activity, which was about 30% of that of the free counterpart. Entrapment method enabled lipase to gain operational stability. Semicontinuous hydrolysis of olive oil using immobilized lipase was also accomplished in a packed-bed reactor with a recycling system. In this reactor, immobilized lipase was observed to have the sufficient activity and stability.