Box-Behnken experimental design was used for three factors (soy protein, sodium nitrate, and stearic acid) and the optimal composition for maximum lipase production (1.7-fold enhancement) was established as soy protein 4.07%, sodium nitrate 0.17%, and stearic acid 0.28% at 28☌ with an agitation rate of 220 rpm for 24 h. Polyoxyethylene (20) sorbitan tristearate, whose side chain is stearic acid, was the most effective carbon source for lipase production. A number of carbon sources including different types of starch, sugar, sugar alcohol, organic acids, and surfactants were investigated. (ATCC 31371) by optimization of the culture medium, for economic production of biodiesel from waste vegetable oil. The aim of this study was to improve the production of an extracellular alkaline lipase from Alcaligenes sp. Finally, the immobilized lipase was used for the production of green apple flavor (i.e., ethyl valerate) in hexane medium. Thermal and storage stabilities were found to be increased upon immobilization.
#S2KI RECOMMENDED ETUNES FREE#
Optimal temperature was 5 ☌ higher for immobilized enzyme than that of the free enzyme. The Vmax values of free and immobilized enzymes were calculated as 926 and 741 U/mg enzyme, respectively. The estimated apparent Km values for the free and immobilized lipase were 2.9 and 8.4 mM, respectively. Kinetic analysis shows that the dependence of lipolytic activity of both free and immobilized lipase on tributyrin substrate concentration can be described by Michaelis–Menten model. The retained activity of the immobilized lipase was 76%. The aminated polypropylene (APP) membrane was used for covalent immobilization of Candida rugosa lipase via glutaraldehyde coupling. The PPC and APP membranes were characterized using SEM, FTIR and contact angle studies.
In this study, a functionalized hydrophobic polypropylene chloride membrane (PPC) was prepared by the amination of chlorinated polypropylene with hexamethylene diamine (APP).
The immobilized lipase was effectively reused in successive batch runs in a solvent-free system for isoamyl acetate synthesis, and only 21% activity was lost after 10 cycles. Finally, esterification reactions have been performed to produce ethyl acetate and isoamyl acetate in a solvent-free system and in n-hexane using lipase-immobilized P(S-DVB)-g-P(S-GMA)-HMDA-GA microspheres. Thermal and storage stabilities increase upon immobilization on the P(S-DVB)-g-P(S-GMA)-HMDA-GA microspheres. In this case, a maximum value of the immobilized enzyme activity 498.5 U g−1 was found with an enzyme loading of 27.6 mg per gram of support. The covalent immobilization of the lipase on microspheres after spacer-arm attachment and glutaraldeyhde coupling was found to be the more effective than the direct binding method. Two different approaches for the covalent immobilization of lipase onto microspheres were studied for the first time: (1) direct immobilization of lipase to the polymer brushes via their epoxy groups, and (2) immobilization of lipase via glutaraldehyde coupling after attachment of a spacer arm (hexamethylendiamine (HMDA)) to the polymer brushes. The alkali-combined lipase significantly enhanced the FAME production rate from wABE, in spite of the presence of the plant pigments, and even when a lower amount of lipase was used as a catalyst.įunctional hairy poly(styrene-b-glycidylmethacrylate) (P(S-GMA)) brushes were generated by grafting from bromoacetylated poly(styrene-divinylbenzene) (P(S-DVB)) microspheres via surface-initiated atom transfer radical polymerization (SI-ATRP). When 0.9% KOH (w/w wABE) was added to the transesterification reaction with only 0.05% lipase (w/w wABE), the maximum FAME production rate improved 120-fold, as compared to that without the addition of KOH. Furthermore, the addition of a small amount of alkali nullified this inhibitory effect and accelerated the FAME production rate. The inhibition of the enzymatic hydrolysis of waste vegetable oil contained in wABE by chlorophyll a alone was competitive, while the inhibition by chlorophyll b alone was non-competitive. The inhibition by a mixture of chlorophyll a and b was found to be competitive. The chlorophylls inhibited the lipase during FAME conversion from wABE.
The impurities were extracted from the wABE with methanol and evaluated by infra-red (IR) spectroscopy, which revealed that some were chlorophyll-plant pigments.
During the vegetable oil refinery process, activated bleaching earth (ABE) is used for removing the impure compounds, but adsorbs vegetable oil up to 35-40% as on a weight basis, and then the wABE is discarded as waste material. This study sought to identify inhibitory factors of lipase catalyzed-fatty acid methyl esters (FAME) production from waste activated bleaching earth (wABE).