Clean-chemistry synthesis of biodegradable tertiary α-substituted carboxylic acids from the corresponding esters through enzymatic processes

A variety of lipases and esterases were tested for the hydrolysis of carboxylic acid ester 1 or similar tertiary α-substituted esters. Carboxylic acid ester 1 is not readily biodegradable under normal hydrolytic conditions. However, the resulting carboxylic acid 2 is biodegradable. In our study we have found that of the biocatalysts used, the most effective were Candida antarctica lipase A (CAL-A), C. antarctica lipase B (CAL-B), and pig liver esterase (PLE). In addition, different ratios of cosolvents have been studied. CAL-B and PLE catalyzed the hydrolysis of ester 1 in 4 h at 30 °C, whereas CAL-A hydrolyzed 1 in 22 h.