Comparative studies on citric acid production by Aspergillus niger and Candida lipolytica using molasses and glucose

TLDR: It appears that product formation by Aspergillus niger is either non-growth associated or partially growth associated depending on the substrate, and Methanol addition changes the nature of product formation in case of Candida lipolytica.

Abstract: Citric acid production by Aspergillus niger NCIM 548 and Candida lipolytica NCIM 3472 has been studied in shake culture using glucose and molasses as carbon sources. Methanol addition (3% v/v) at 40 h of fermentation enhanced the production of citric acid by Aspergillus niger whereas a reduction in citric acid production by Candida lipolytica was observed with addition of methanol. Maximum citric acid concentration of 12 kg/m3 was obtained with Aspergillus niger using molasses in the presence of methanol, while maximum citric acid concentration of 8.4 kg/m3 was obtained with Candida lipolytica using glucose without methanol. It appears that product formation by Aspergillus niger is either non-growth associated or partially growth associated depending on the substrate. Methanol addition changes the nature of product formation in case of Candida lipolytica.