Specificity of Carica papaya Latex as Biocatalyst in the Esterification of Fatty Acids with 1-Butanol

Papaya (Carica papaya) latex, reportedly known to have good lipolytic activity, has been evaluated as biocatalyst in the esterification of various fatty acids with 1-butanol in the presence of myristic acid as the reference standard. C. papaya latex strongly discriminates against fatty acids having a cis-4 unsaturation, e.g. all-cis-4,7,10,13,16,19-docosahexaenoic acid, cis-6 unsaturation, e.g. petroselinic (cis-6-octadecenoic), γ-linolenic (all-cis-6,9,12-octadecatrienoic), and stearidonic (all-cis-6,9,12,15-octadecatetraenoic) acids, and cis-8 unsaturation, e.g. dihomo-γ-linolenic (all-cis-8,11,14-eicosatrienoic) acid. Fatty acids having cis-5 unsaturation, e.g. all-cis-5,8,11,14,17-eicosapentaenoic acid, and those having a cis-9 unsaturation, e.g. oleic (cis-9-octadecenoic) and α-linolenic (all-cis-9,12,15-octadecatrienoic) acids are very well accepted as substrates. Fatty acids having hydroxy groups, e.g. ricinoleic (12-hydroxy-cis-9-octadecenoic) acid and 12-hydroxystearic acid, epoxy groups, e.g. trans-9,10-epoxystearic acid, and cyclopentenyl groups, e.g. hydnocarpic [(11-(2‘-cyclopentenyl)undecanoic] acid and chaulmoogric [13-(2‘-cyclopentenyl)tridecanoic] acid are also well accepted as substrates. The observed substrate specificities are similar to those reported for lipase preparations from microorganisms, animals, and plants. Keywords: Carica papaya latex; plant lipase, biocatalyst; enzymatic esterification; fatty acid specificity