Overnight cultures were prepared by inoculating 10 mL of LB (supplemented with 50 μg mL -1 kanamycin) with a single colony and growing for 16 hours at 37 o C at 200 rpm. The overnight culture was then used to inoculate a baffled flask containing 400 mL TB media and 50 μg mL -1 kanamycin and incubated at 37 o C at 250 rpm until optical density at 600 nm (OD600) of 0.6. The culture was cooled to 20 o C and isopropyl-β-D-thiogalactoside (IPTG) was added to a final concentration of 0.1 mM to induce expression of the transaminase and further incubated overnight at 20 o C at 180 rpm. Cells were centrifuged at 4000 rpm for 30 min and stored as pellets at -20 o C.