There's No Industrial Biocatalyst Like Hydrolase: Development of Scalable Enantioselective Processes Using Hydrolytic Enzymes1

Chiral, racemic esters, ethyl (±)-tetrahydrofuran-2-carboxylate 4c, methyl (±)-α-phenylpropionate 9b, methyl (±)-5,5-dimethyl-1,3-thiazolidine-4-carboxylate 12a, 2-methoxyethyl (±)-1-(4- tert -butylphenyl)-2-oxopyrrolidine-4-carboxylate 15a, (±)-1-benzyloxy-3-chloropropan-2-yl hydrogen succinate 18c, and (±)-3-butyryloxyquinuclidinium butyrate [(±)- 20b · n -PrCO 2 H], are resolved kinetically by enantioselective hydrolysis catalyzed by an Aspergillus melleus protease [ E = 60; 93.9% ee and 35% yield for ( R )-tetrahydrofuran-2-carboxylic acid 4a ], a Klebsiella oxytoca hydrolase [ E > 200; 99.5% ee and 36% yield for ( S )-α-phenylpropionic acid 9a ], a K . oxytoca hydrolase [ E = 145; 97.7% ee and 34% yield for ( R )-5,5-dimethyl-1,3-thiazolidine-4-carboxylic acid 12b ], a Bacillus brevis protease [ E = 77; 99% ee and 45% yield for ( S )- 15a ], a Serratia marcescence esterase [ E = 49; 99% ee and 43% yield for ( S )- 18c ], and an A . melleus protease [ E = 96; 96% ee and 42% yield for ( R )- 20b ], respectively. Each enzymatic process is discussed with focus on the following tactical issues: (1) identification of a hydrolase with high enantioselectivity, (2) substrate concentrations not less than 1 M that allow for industrially viable volume efficiency (space−time yield), (3) product separation by partition between organic and aqueous phases, and (4) alleviation of a hydrolysate inhibiting the enzymatic activity.