Propyl laurate ester

The activity of both Novozym 435 and crosslinked Novozym 435 was measured using the standard PLU-assay. The PLU (propyl laurate units) assay is a method to determine the activity of immobilized lipases by ester synthesis. One PLU corresponds to 1 pmol of propyl laurate formed from condensation of lauric acid and 1-propanol per gram of enzyme per minute under specified conditions. The PLU value is determined by measuring the area under the peak of formed propyl laurate versus a standard sample of propyl laurate with known concentration using a gas chromatograph with an FID detector. Crosslinked Novozym 435 showed an activity of 4800 PLU g"1, whereas the activity of Novozym 435 before crosslinking was measured to be 12200 Pl.U g 1. 

Lipase Activity The ester synthesis activity of Novozym 435 is expressed in Propyl Laurate Units (PLU/g). The activity of Novozym 435 used for our synthesis was 7000 PLU/g. 

More recently Webb et al. (1952) reported no isopropyl alcohol in a wine fusel oil sample. They did find 4.1% n-propyl, 1.9% n-butyl, 4.9% ( — )-sec-butyl, 18.3% isobutyl, 9.6% ( —)-2-methyl-l-butanol, 54% isoamyl, trace of n-amyl, 1.5% n-hexyl, 5.6% esters, and traces of acetic and butyric acids and acetal. The esters included 0.19% ethyl caproate, 0.60% ethyl caprylate, 0.52% isoamyl caprylate, 1.32% ethyl caprate, 0.38% isobutyl caprate, 0.58% ethyl laurate, 0.25% ethyl palmitate, a trace of butyrate ester, 0.06% myristate ester. Probably present were methyl salicylate, isoamyl caprate, active amyl caproate, isoamyl caproate, active amyl caprylate, isobutyl caprylate, active amyl caprate, active amyl laurate, and isoamyl laurate. 

---