*2.8.4. Molecular sieve*

In order to promote the synthesis of phenolic lipids by shifting the reaction toward synthesis rather than hydrolysis, a reduction of water content in the reaction mixture can be accomplished through the addition of molecular sieve pellets as dehydrating agents. Li et al. [111] reported that the addition of molecular sieves increased the rate and conversion yield; this is due to the effect of the molecular sieves to sequester the water layer from the enzyme molecule which is essential for the water-enzyme interaction. Mellou et al. [112] found that the conversion yield of rutin during esterification reaction with oleic acid catalyzed by immobilized *C. antarctica* lipase B in different solvents was varied from 37 to 71% under the use of molecular sieves (100 mg/ ml). However, Karboune et al. [113] observed 28 and 35% decrease in the maximum conversion yield upon the addition of 10 mg/ml of molecular sieves to the lipase-catalyzed biosynthesis of cinnamoylated lipids. This could be explained by the fact that molecular sieves promote the lipase-catalyzed synthesis reactions by dehydrating; however, excess of molecular sieves will capture the necessary water of enzyme, which may inhibit the enzyme activity.
