The C. glutamicum AJ110135 having an enhanced AKfbr gene and the C. glutamicum AJ110135 having an enhanced PC gene selected in Example 3 (2) and (3), respectively were cultured in the flask evaluation medium (100 g of glucose, 1 g of magnesium sulfate heptahydrate, 55 g of ammonium sulfate, 1 g of potassium dihydrogen phosphate, 0.01 g of iron sulfate heptahydrate, 0.01 g of manganese sulfate pentahydrate, 2 mg of thiamine hydrochloride, 0.5 mg of biotin, 5 mg of nicotine amide, 1.05 g of soy concentrate (hydrolyzed soy protein, as total nitrogen content) and 50 g of calcium carbonate were adjusted in 1 L of water to pH 7.2, and kanamycin was added at a final concentration of 25 mg/L and chloramphenicol was added at a final concentration of 5.0 mg/L) at 30° C. for 71 hours at 120 rpm. As the control experiment, the C. glutamicum AJ110135 with the pVC7 was cultured in the above flask evaluation medium with kanamycin at a final concentration of 25 mg/L for 71 hours. As a result, glucose was completely consumed in all of the experiments. 1.0 g/L of 3,4-AHBA was accumulated in the culture of C. glutamicum AJ110135 having the enhanced AKfbr gene, and 0.6 g/L of 3,4-AHBA was accumulated in the culture of C. glutamicum AJ110135 having the enhanced PC gene (Table 2). Meanwhile, 0.5 g/L of 3,4-AHBA was accumulated in the culture of C. glutamicum AJ110135 having introduced pVC7 as the control experiment. From the above results, the ability to form AHBA was improved in C. glutamicum AJ110135 having the enhanced AKfbr gene and C. glutamicum AJ110135 having the enhanced PC gene compared with C. glutamicum AJ110135 as the control.
