Hyperproduction of Sebaceous cis-6-Hexadecenoic Acid by Esterase-Reduced Mutant of Rhodococcus sp. Strain

cis -6-Hexadecenoic acid is a major component of human sebaceous lipids that is involved in skin self-sterilization and atopic dermatitis amelioration. It can be prepared by hydrolysis of isopropyl cis -6-hexadecenoate produced by resting cells of Rhodococcus sp. strain KSM-MT66. To devise an economical industrial-scale process for the production of this rare fatty acid, we optimized the conditions for growing rhodococcal cells. Mg 2+ and Fe 2+ ions are essential for the efficient production of isopropyl cis -6-hexadecenoate. To further increase the production of isopropyl cis -6-hexadecenoate, we created a mutant strain (T64) with reduced esterase activity by random mutagenesis using UV irradiation of MT66. Under an optimized condition, the mutant T64 produced more than 60 g l −1 isopropyl cis -6-hexadecenoate in a 4-d cultivation, corresponding to about 52 g l −1 cis -6-hexadecenoate.