Process for producing alpha-hydroxy acid or alpha-hydroxyamide by microorganisms

A process for producing .alpha.-hydroxy acids or .alpha.-hydroxyamides by microorganisms, in which an .alpha.-hydroxynitrile compound represented by the following general formula (1) or a mixture consisting of an aldehyde represented by the following general formula (2) and prussic acid is allowed to undergo a microbial reaction to produce the corresponding .alpha.-hydroxy acid or .alpha.-hydroxyamide represented by the following general formula (3), wherein the improvement resides in that phosphite ions or hypophosphite ions are allowed to be present in the reaction system:

• ##STR2## wherein R represents a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkenyl group, a substituted or unsubstituted cycloalkyl group, a substituted or unsubstituted alkoxy group, a substituted or unsubstituted aryl group, a substituted or unsubstituted aryloxy group, or a substituted or unsubstituted, saturated or unsaturated heterocyclic group, and X represents a carboxyl group or an amido group.