Process for the manufacture of tertiary, optically active aliphatic compounds

A process for producing a tertiary optically active aliphatic compound of the formula ##STR81## wherein X' and Y' are different functional groups, one is carboxy, esterified carboxy and the other is carboxy, hydroxymethyl, esterified carboxy or etherified or esterified hydroxymethyl;

• wherein the carboxy and hydroxymethyl groups are lactonized with one another with the formation of the group --CO--O--CH.sub.2 -- or --CH.sub.2 --O--CO--, and wherein when X' is alkyl-etherified hydroxymethyl, Y' is also hydroxymethyl or esterified hydroxymethyl, comprising fermentatively hydrogenating an olefinic compound of the formula:
• ##STR82## wherein X is carboxy, esterified carboxy, hydroxymethyl etherified or esterified hydroxymethyl and Y is carboxy, formyl, hydroxymethyl, esterified carboxy, acetalized formyl or etherified or esterified hydroxymethyl;
• wherein X and Y are different functional groups;
• wherein when X is hydroxymethyl or esterified hydroxymethyl, Y is carboxy, formyl, or acetalized formyl and when Y is hydroxymethyl or esterified hydroxymethyl, X is esterified carboxy or alkyl-etherified hydroxymethyl, with an aerobic or facultative microorganism capable of hydrogenating a double bond situated in an aliphatic chain between a CH and methylated CH moiety in an aqueous medium to obtain said tertiary optically active aliphatic compound as a fermentation product.