Solvent polarity influences product selectivity of lipase‐mediated esterification reactions in microaqueous media

Abstract

Esterification reactions were evaluated by using lipases fromRhizomucor miehei (Lipozyme IM20) andPseudomonas cepacia (PS‐30) with equimolar levels (1.77 mmol) of undecanoic acid and glycerol or 1,3‐propanediol (1,3‐PD) or 1,2‐propanediol (1,2‐PD) in organic solvents of log P (partition coefficient between 1‐octanol/water) values of (−0.33–4.5. Reaction yields (percentage of esterified undercanoate) with glycerol ranged from 1.4 to 72%, with greatest yields observed in solvents of log P 4.0–4.5 for Lipozyme, whereas the PS‐30 lipase was similarly effective (27–38% yield) over the full range of solvent polarities. For both enzymes, as solvent apolarity increased, so did the extent of acylation of glycerol in the final product mixture. Reaction yields with 1,3‐PD ranged from 8.1 to 64% for Lipozyme and from 18 to 84% for PS‐30 lipase, with greatest yields observed for both enzymes in solvents of log P values in the range 1.2–5.0. For both lipases, the shift to greater solvent apolarity was accompanied by an increased molar ratio of diacylated‐1,3‐PD/monoacylated‐1,3‐PD in the product mixture. Reaction yields with 1,2‐PD ranged from 2.5 to 45% for Lipozyme and from 12 to 52% for PS‐30 lipase, with greatest yields observed in solvents of log P values in the ranges 1.4–1.9 and 1.4–4.5, respectively. The shift to greater solvent apolarity was accompanied by an increased molar ratio of diacylated‐1,2‐PD: monoacylated‐1,2‐PD in the product mixture, except for Lipozyme in the three most apolar solvents (log P of 3.5–4.5) in which there was a general attenuation of activity. These results suggest the existence of a solvent polarity influence on reaction product selectivity in multiproduct reactions, which can be partially explained on the basis of differential solvation and extraction properties of solvents.

Optimization of Selective Lipase‐Catalyzed Feruloylated Monoacylglycerols by Response Surface Methodology

“…The choice of the solvent was based on solvent polarity, which was the main factor influencing the selectivity of lipase-catalyzed reaction [8]. Several research groups pointed out that solvent with Log P \ 2 could increase the specific production of monoacylglycerols [7]. On the other hand, solvent with Log P [ 2 was favorable for relatively high activity of enzyme.…”

“…On the other hand, solvent mixtures as reaction media have been employed in the selective enzyme-catalyzed reactions, and the advantages of using solvent mixtures versus other strategies have been discussed [5]. However, few studies applied systematically statistical methods to investigate the effect of solvent mixtures on the selectivity in enzyme-catalyzed reactions [6,7]. Response surface methodology (RSM) is a popular and effective statistical technique for the investigation of complex process.…”

Lipase-Catalyzed Deacylation by Alcoholysis: A Selective, Useful Transesterification Reaction

“…Fatty acyl specificity has been related to structural features of lipases [54][55][56] and the chain length substrate selectivity of various lipases has been studied in a few works [57][58][59][60], including transesterification of methyl esters of C8 to C18 fatty acids [61]. Fatty acyl specificity has been related to structural features of lipases [54][55][56] and the chain length substrate selectivity of various lipases has been studied in a few works [57][58][59][60], including transesterification of methyl esters of C8 to C18 fatty acids [61].…”

Solvent effect on hydrogenolysis of glycerol to 1,2-propanediol over Cu–ZnO catalyst

“…Hence they drew a conclusion that protic solvents such as ethanol and water favored the formation of 1,3-propanediol from glycerol, meanwhile binary solvents containing a ACCEPTED MANUSCRIPT 5 protic component showed a synergetic solvent effect on the selective dehydroxylation of glycerol to 1,3-propanediol. Kuo et al [22] proved that the solvent polarity had an influence on the reaction product selectivity for esterification reactions, which could be partially explained on the basis of different solvation and extraction properties of solvents. Unfortunately, up to now, there is still no uniform conclusion in regard to solvent selection as well as its action mechanism that can be drawn to adapt to diverse reactions.…”

“…In general, solvent can play an important role in determining the catalytic performance for many reactions [21][22][23]. Gong et al [21] found the use of water or ethanol as a solvent reached a selectivity to 1,3-propanediol of 25.7%, 23.0% respectively, which was obviously higher than that of 1,3-dimethyl-2-imidazolidinone (DMI) or sulfolane.…”