A bio-generated Fe(iii)-binding exopolysaccharide used as new catalyst for phenol hydroxylation

Abstract

The hydroxylation of phenol with aqueous H2O2 to afford catechol and hydroquinone was studied in a biphasic reaction medium, as well as in pure water, in the presence of a bio-generated iron(III) catalyst. This catalyst was purified from a culture of Klebsiella oxytoca BAS-10 growing under anaerobic conditions, with Fe(III)-citrate as the energy and carbon source. The overproduction of an exopolymer (EPS) encrusted bacterial cells. The EPS, binding Fe3+, (Fe-EPS), was extracted and studied before and after a reaction with phenol. Some of the reaction’s parameters, such as temperature, pH, and molar ratio between reagents and catalyst, were investigated to identify the best compromise between conversion and selectivity. The results could be useful either from a synthetic point of view or to support the biodegradation of aromatic substrates.