Production of esterase by Fusarium culmorum grown in the presence of different concentrations of di(2-ethylhexyl) phthalate and calcium ion in submerged fermentation

Phthalates are plastic additives used as plasticizers in the manufacture of flexible plastic materials. These compounds, such as di(2-ethylhexyl) phthalate (DEHP) are toxic substances to the environment and human health, and have been detected asenvironmental pollutants. In this study, the activity of esterase produced by Fusarium culmorum grown in media supplemented with different concentrations of DEHP (1.5, 3 and 4 g/L) and calcium ion (0.1 and 0.5 g/L) in submerged fermentation was characterized by biochemical tests and polyacrylamide gel electrophoresis. The greatest esterase activity was observed in cultures grown in media added with 3 g of DEHP/L and 0.5 g of calciumion/L, followed by those cultures grown in media containing 1.5 g of DEHP/L. Whereas cultures grown on 4 g of DEHP/L had the lowest esterase activity. In general, cultures added with 0.5 g of calcium ion/L had the maximum enzymatic activity and the highest enzymatic productivity in the media tested. High concentration of DEHP were used as the sole source of carbon and energy by F. culmorum. It is suggested that the calcium ion favored the esterase production during the DEHP biodegradation. However, further studies are needed to understand the relationship between calcium ion, fungal growth, and enzyme production to provide the appropriate concentration of this ion in the culture medium.