Utilization of immobilized lipases as catalysts in the transesterification of non-edible vegetable oils with ethanol

Abstract

-This work reports the use of commercially available immobilized lipase preparations (Novozym® 435 and Lipozyme TL IM, both from Novozymes, and Lipase PS IM from Amano) as catalysts in the transesterification reaction of different alkyl-chain triglycerides with ethanol. The ethanolysis of native oils from Brazilian Amazon plants andiroba (Carapa guianensis), babassu (Orbignya sp.), jatropa (Jatropha curcas), and palm (Elaeis sp.) was studied in a solvent-free system. In a typical reaction, the immobilized preparations were added to the mixture of vegetable oil-to-ethanol in a molar ratio of 1:9. The reactions were performed at 50 °C for a maximum period of 48 h. Under the conditions used, all the immobilized lipase preparations were able to generate the main esters of fatty acids present in the tested feedstocks, and both the reaction rate and ester yield were dependent on the source of lipase and vegetable oil. The viscosity values for the samples obtained in each reaction displayed a consistent reduction in relation to their original feedstocks, which also confirms the high conversion of triglycerides to ethyl esters (99.8-74.0%). The best performances were obtained with Amano PS IM and Novozym® 435, with the biodiesel samples from the babassu and jatropha oils exhibiting viscosity values in accordance with those predicted by the technical standards of ASTM D6751 (1.9-6.0 mm 2 /s). Lipozyme TL IM displayed an unsatisfactory performance, indicating that the conditions of the transesterification reaction should be improved. This comparative study using different catalysts and several vegetable oil sources with varying fatty acid compositions is particularly important for all tropical countries with a diversity of native vegetable oil sources.

Statistical Optimization of Biodiesel Production from Salmon Oil via Enzymatic Transesterification: Investigation of the Effects of Various Operational Parameters

“…In the present study, tert-butanol dissolved both methanol and glycerol, which eliminated the adverse effects of glycerol accumulation during the transesterification process. As reported in previous studies, tert-butanol is not a substrate for lipases, and it does not act on tertiary alcohols [57][58][59].…”

Assessing Waste Cooking Oils for the Production of Quality Biodiesel Using an Electronic Nose and a Stochastic Model

“…Considerable variability was also observed in the peroxide indices of the WCO samples, which ranged from 1.98 to 71.82 mequiv kg –1 , indicating that many samples had undergone considerable oxidative degradation. The kinematic viscosity of WCO samples varied between 33.15 and 61.84 mm2 s –1 , values that were much higher than those (29.80–47.80 mm 2 s –1 ) reported previously by Tiosso et al However, the oil samples evaluated in the present study had all been subjected to the complex chemical reactions that occur during the frying process.…”

“…Knowledge of the physicochemical properties of a WCO is essential to assess the suitability of the material for the production of biodiesel, since these characteristics influence the transesterification reaction and, consequently, the quality of the biofuel so formed. 20 The acidity indices of the WCO samples were highly variable and ranged from 0.39 to 12.59 mg KOH g −1 (Table 1). High acidity indices result from oxidation and hydrolysis reactions that oils undergo during the frying process or storage.…”