| abstract |
Aliphatic tricarboxylic acids, as exemplified by 9-carboxy-1,18-octadecanedioic acid, may be prepared by the biotransformation of an olefinic monocarboxylic acid such as oleic acid to the corresponding olefinic dicarboxylic acid, preferably 1,18-octadec-9-enedioic acid, in the presence of a strain of yeast, such as a strain of Candida tropicalis, followed by the carboxylation of the olefinic dicarboxylic acid by reaction with carbon monoxide and water in the presence of a catalyst. The product tricarboxylic acids are useful as branching agents for polycarbonates. |