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Partial characterization of esterases from Fusarium culmorum grown in media supplemented with di (2-ethyl hexyl phthalate) in solid-state and submerged fermentation Caracterización parcial de esterasas de Fusarium culmorum crecido en presencia de di(2-etil hexil ftalato) en fermentación sólida y sumergida

Dibutyl phthalate (DBP) is one of the most abundantly produced and used plasticizers and is incorporated into plastic to make it more flexible and malleable. DBP has been found to be an environmental contaminant and reported as an endocrine disruptor. Therefore, it is crucial to develop ecofriendly alternatives to eliminate phthalate pollution. In the present research, the growth of F. culmorum and F. oxysporum in the presence of DBP was studied in liquid fermentation. The esterase activity, specific growth rate, and growth and enzymatic yield parameters were determined in DBP-supplemented media (1500 or 2000 mg/L) and in control medium (lacking DBP). These results show that in general, for both Fusarium species, the highest esterase activities, specific growth rates, and yield parameters were observed in media supplemented with DBP. It was observed that 1500 and 2000 mg of DBP/L did not inhibit F. culmorum or F. oxysporum growth and that DBP induced esterase production in both fungi. These organisms have much to offer in the mitigation of environmental pollution caused by the endocrine disruptor DBP. This study reports, for the first time, esterase production during the degradation of high concentrations (i.e.1500 and 2000 mg/L) of DBP by F. culmorum F. oxysporum.

Tween 80 is a widely used non-ionic surfactant that is added to culture media to make hydrophobic substrate available to microorganisms. Because of this surfactant widespread use, it is important to understand how it affects microbial growth and enzyme production. In this work, the effect of different concentrations (100, 400 and 600 l/L; v/v) of Tween 80 (as the sole carbon source) on the biomass production, esterase activities (assessed through biochemical tests and zymographic assays) and protein content of Fusarium culmorum grown in liquid fermentation was determined. The specific growth rate (μ), biomass yield (YX/S), esterase yield (YE/X), esterase productivity (P), maximal enzymatic activity (Emax), and specific rate of enzyme production (qp) were also estimated. A control medium added with glucose was used. The highest μ was showed in the medium added with 100 l of Tween 80/L. However, the greatest esterase activity was observed in those media containing the highest concentrations of Tween 80 ( energy source and it also induced the esterase production by F. culmorum. Tween 80 concentration is positively correlated with the number of esterase isoforms produced by this fungus. The higher the Tween 80 concentration (400 μl/L and 600 μl/L, v/v), the more number of esterase isoforms will be induced. However, lower concentration (100 μl/L) of Tween 80/L did not show a significant effect on the induction of the esterase activity.400 l/L and 600 l/L; v/v). These results show that Tween 80 was used as the sole carbon and