Transesterification Of Crude Palm Oil To Fatty Acid Methyl Esters (Fame) Mediated By Lipase In Batch And Continuous Systems
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Date
2011-01
Authors
Sim, Jia Huey
Journal Title
Journal ISSN
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Publisher
Universiti Sains Malaysia
Abstract
The rapid increase in the crude oil prices due to diminishing reserves of fossil fuels and the increased rate of world energy consumption have drawn attention of the researchers towards biodiesel as an alternative energy source. The transformation of palm oil into value-added product biodiesel can help to increase its commercial value of palm oil. The green technology of enzymatic transesterification with crude palm oil (CPO) as feedstock for biodiesel production has been studied in the present research. Lipozyme TL IM was found as a suitable biocatalyst for CPO transesterification with stable FAME productivity of 54.85 - 63.14% within the temperature range of 30 - 60°C. The recovery of Lipozyme TL IM for repeated usage was simple and relatively cheap (USD 125.91/kg) as compared to the competitive Novozym 435 (USD 1671.19/kg). Methanol inhibition was alleviated successfully using CMD where 96.15% FAME yield was achieved at 0.37: 0.10: 0.53 proportions of CPO: methanol: tert-butanol. Process operation with minimum mass transfer limitations was defined at 150 rpm, 6.65 wt% enzyme loading and 4 hr reaction time in order to attain 96.15% FAME yield. A kinetic model that accounted for both lipase activation and deactivation effects was proposed and FAME yield corresponding to temperature and reaction time variation was predicted from the model (R2 = 0.99). The most suitable operative temperature was 40°C because the lipase denaturation rate of 1.10 x 10-2 hr-1 at 40°C was overwhelmed with the gain of 2.66% FAME yield/min. The lipase-catalyzed transesterification of CPO mediated with tert-butanol could be elucidated by ping-pong bi-bi mechanism with maximum
reaction rate, max V 1.45 mmol/ml.min, CPO binding constant, a K 1.59 mmol/ml
and methanol binding constant, b K 1 mmol/ml. The CPO transesterification in
continuous PBR system showed high catalytic efficiency with 90% FAME yield and
produced at 0.70 ml/min feed flowrate, 3.50 cm PBR height and 355 μm biocatalyst
particle size. The high FAME yield achieved in this study shows that it is feasible to
produce biodiesel from CPO via enzymatic transesterification.
Description
Keywords
Transesterification of crude palm oil to fatty acid methyl esters , mediated by lipase in batch and continuous systems