Process for preparing (+)-homopilopic acid

A process for preparing (+)-homopilopic acid and salts thereof, which comprises, in a first step, hydrolyzing a mixture of (+)-homopilopic acid ester of the general formula (I):

• ##STR10## wherein R.sub.1 denotes a straight or branched C.sub.1 -C.sub.10 hydrocarbon, and (-)-homopilopic acid ester of the general formula (II):
• ##STR11## wherein R.sub.2 denotes a straight or branched C.sub.1 -C.sub.10 hydrocarbon, using either a hydrolase selected from the group consisting of a lipase, an esterase, and a cholesterol esterase, or a microorganism selected from the group consisting of Brevibacterium ketoglutamicum ATCC 1588 and Escherichia coli IFO 3366, or a crude enzyme solution thereof obtained by disrupting cells of said microorganism wherein said crude enzyme solution contains at least one enzyme selected from the group consisting of a lipase, an esterase, a cholesterol esterase, and a lipoprotein lipase, recovering the unreacted (+) -homopilopic acid ester, and thereafter, in a second step, hydrolyzing said unreacted (+)-homopilopic acid ester using either a hydrolase selected from a lipase or an esterase, or a microorganism selected from the group consisting of Escherichia coli IFO 3366, Nocardia rubropertincta FERM BP-3641, Bacillus subtilis IFO 3108, Brevibacterium ketoglutamicum ATCC 15588, and Rhizomucor miehei IFO 9740, or a crude enzyme solution thereof obtained by disrupting cells of said microorganism wherein said crude enzyme solution contains at least one enzyme selected from the group consisting of a lipase, an esterase, a cholesterol esterase, and a lipoprotein lipase.