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Abstract
Kinetics of kojic acid fermentation by Aspergillus flavus Link 44-1 using various sources of carbon [glucose, xylose, sucrose, starch, maltose, lactose or fructose] and nitrogen [NH^sub 4^Cl, (NH^sub 4^)^sub 2^S^sub 2^O^sub 8^, (NH^sub 4^)^sub 2^NO^sub 3^, yeast extract or peptone] were analyzed using models based on logistic and Luedeking-Piret equations. The highest kojic acid production (39.90 g l^sup -1^) in submerged batch fermentation was obtained when 100 g l^sup -1^ glucose was used as a carbon source. Organic nitrogen sources such as peptone and yeast extract were favorable for kojic acid production as compared to inorganic nitrogen sources. Yeast extract at 5 g l^sup -1^ was optimal. The optimal carbon to nitrogen (C/N) ratio for kojic acid fermentation was 93.3. In a resuspended cell system, the rate of glucose conversion to kojic acid by cell-bound enzymes increased with increasing glucose concentration up to 70 g l^sup -1^, suggesting that the reaction followed the Michaelis-Menten enzyme kinetic model. The value of K^sub m^ and V^sub max^ for the reaction was 18.47 g l^sup -1^ glucose and 0.154 g l^sup -1^ h^sup -1^, respectively. Journal of Industrial Microbiology & Biotechnology (2000) 25, 20-24.[PUBLICATION ABSTRACT]