Specificity of papaya lipase in esterification of aliphatic alcohols - A comparison with microbial lipases

Straight-chain saturated C4 to C18 alcohols and unsaturated C18 alcohols, s uch as cis-9-octadecenyl (oleyl), cis-6-octadecenyl (petroselinyl), cis-9,c is-12-octadecadienyl (linoleyl), all-cis-9,12, 15-octadecalrienyl (alpha -l inolenyl), and all-cis-6, 9,12-octadecatrienyl (gamma -linolenyl) alcohols, were esterified with caprylic acid using papaya (Carica papaya) latex lipa se (CPL) and immobilized lipases from Candida antarctica (Lipase B, Novozym , NOV) and Rhizomucor miehei (Lipozyme, LIP) as biocalalysts. With CPL, hig hest activity was found for octyl and decyl caprylate syntheses, whereas bo th NOV and LIP showed a broad chain-length specificity toward the alcohol s ubstrates. CPL strongly discriminated against all C18 alcohols studied, rel ative to n-hexanol, whereas the microbial lipases accepted the C18 alcohols as substrates nearly as well as n-hexanol. Both petroselinyl and gamma -li nolenyl alcohol were very well accepted as substrates by NOV as well as LIP , although the corresponding fatty acids, i.e., petroselinic and gamma -lin olenic acid, are strongly discriminated against by several microbial and pl ant lipases, including LIP and CPL.