The kinetic resolution of BMBA was used as a model reaction to assess the catalytic activity of free and membrane-immobilized transaminases. Racemic BMBA was reacted with pyruvate, to produce BAP and either L-or D-alanine leaving unreacted R-or S-BMBA when using an S-or a R-selective TA, respectively (Figure ). When catalytic tests were run with immobilized transaminases, one disk of 5 cm 2 of membrane support was employed.