The aliquot of culture of B. megaterium ACBT03 in cryo-tubes after thawing were used to inoculate 500 ml baffle type shake flask containing 150 ml of medium. After inoculation, flasks were incubated over night at 28 8C, 300 rpm. Five milliliters of pre-culture was transferred into 50 ml of the same medium to which colchicine and thiocolchicine were added to obtain 3, 5,
7 and 10 g/l final concentration. The culture were incubated for 3 days in the same conditions as described above, and every 6 h, samples were taken to evaluate the growth level (measured absorbance at 600 nm), the 3-DMC and 3-DMTC production by TLC and HPLC, the sterility on LB agar, and for the microscopic examination.