Enzymatic Interesterification of Palm Stearin and Coconut Oil by a Dual Lipase System

Abstract

Enzymatic interesterification of palm stearin with coconut oil was conducted by applying a dual lipase system in comparison with individual lipase-catalyzed reactions. The results indicated that a synergistic effect occurred for many lipase combinations, but largely depending on the lipase species mixed and their ratios. The combination of Lipozyme TL IM and RM IM was found to generate a positive synergistic action at all test mixing ratios. Only equivalent amount mixtures of Lipozyme TL IM with Novozym 435 or Lipozyme RM IM with Novozym 435 produced a significant synergistic effect as well as the enhanced degree of interesterification. The interesterification catalyzed by Lipozyme TL IM mixed with thermally inactivated immobilized lipase preparations indicated that the carrier property may play an important role in affecting the interaction of two mixed lipases and the subsequent reactions. A dual enzyme system, consisting of immobilized lipases and a non-immobilized one (Lipase AK), in most cases apparently endows the free lipase with a considerably enhanced activity. 70% Lipase AK mixed with 30% immobilized lipase (Lipozyme TL IM, RM IM and Novozym 435) can achieve an increase in activity greater than 100% over the theoretical value when the reaction proceeds for 2 h. The co-immobilization action of the carrier of the immobilized lipases towards the free lipase was proposed as being one of the reasons leading to the synergistic effect and this has been experimentally verified by a reaction catalyzed by a Lipase AK-inactivated preparation. No apparently synergistic effect of the combinations of Lipozyme TL IM and RM IM was observed when the dual enzyme systems applied to the continuous reaction performed in a packed bed reactor.In brief, this work demonstrated the possibility of increasing the reaction rate or enhancing the degree of conversion by employing a dual lipase system as a biocatalyst.

Enzymatic Biodiesel Synthesis From Acid Oil Using a Lipase Mixture

“…Ibrahim et al 6 also observed a synergistic effect for the Lipozyme TL IM -RM IM dual system in the interesterification of palm stearin and coconut oil.…”

“…The use of combined enzyme resulted in higher amount of ester produced when the total amount of lipases was lower than 7 wt.%. Ibrahim et al 6 demonstrated that a positive interaction between two mixed lipases does not always happen. According to these authors, the interactive effect differs for different lipase combinations and mixing ratios, and some experiments with blends of different lipases showed an antergic effect.…”

“…According to these authors, the interactive effect differs for different lipase combinations and mixing ratios, and some experiments with blends of different lipases showed an antergic effect. 6 Considering these results, the enzymatic synthesis of biodiesel from acid oil using a mixture of lipases in a total concentration of 7 wt.% was further investigated. According to the results shown in Table 2 and Figure 3, an amount of Lipozyme TL IM and RM IM higher than 7 wt.% did not result in higher ester content.…”

“…Moreover, the support of the immobilized lipases could alter the biocatalyst performance in the presence of natural substrates like vegetable oils. 5,6 The use of a mixture of lipases, which were obtained from different sources, have different specificities, and were immobilized on different supports, could enhance biodiesel rate and yield. There are several reports in which mixtures of different types of lipases were used successfully to catalyze transesterification and interesterification reactions.…”

“…There are several reports in which mixtures of different types of lipases were used successfully to catalyze transesterification and interesterification reactions. 4,[6][7][8][9][10] About 75% of the biodiesel produced in Brazil is derived from soybean oil. However, in Brazil, there are other sources of vegetable oils, like Jatropha curcas, Acrocomia aculeate, and palm oils that are interesting for biodiesel production, as they have higher productivity compared with soybean oil.…”