Process for producing optically-active ortho-substituted mandelic acid compound

A process for producing an optically-active ortho-substituted mandelic acid compound represented by the formula (2):

• wherein R1 represents an optionally-substituted amino group or an optionally-substituted alkoxy group, R2 represents a C1-8 alkyl group optionally substituted with C1-4 alkoxy, and the carbon atom with a symbol * is an asymmetric carbon atom;
• the process comprising bringing an ortho-substituted phenylglyoxalic acid compound represented by the formula (1):
• wherein R1 represents an optionally-substituted amino group or an optionally-substituted alkoxy group, and R2 represents a C1-8 alkyl group optionally substituted with C1-4 alkoxy;
• into contact with a microorganism or a treated product thereof, the microorganism having an ability of reducing the compound of the formula (1) into the optically-active ortho-substituted mandelic acid compound of the formula (2) and being selected from the microorganism group consisting of the genus Aquaspirillum, the genus Xanthomonas, the genus Curtobacterium, the genus Flavobacterium, the genus Sphingomonas and the genus Stenotrophomonas.