Pentachlorophenol removal by Rhizopus oryzaeCDBB‐H‐1877 using sorption and degradation mechanisms

Abstract

BACKGROUND Pentachlorophenol (PCP) is a pollutant of soil and water and it is very toxic to humans and aquatic life. The use of PCP is now restricted or prohibited in development countries, but many areas of the world remain contaminated. Fungi, mainly basidiomycetes, have been studied as a means to remove PCP. However, little is known of the mechanisms used by zygomycetes to remove PCP. RESULTS The effect of two initial amounts of PCP and of two carbon and nitrogen sources on the metabolic response was assayed by determining kinetic and stoichiometric parameters of fungal growth, intermediates, sorption capacity, and abiotic losses of PCP. Independently from carbon sources, sorption was observed. Cultures with glucose–ammonium sulfate and 2 mg PCP yielded 0.116 µg of pentachloroanisole and 10.46 µg of chlorinated compounds. Cultures with glutamic acid–sodium nitrate and 2 mg PCP yielded 6.81 µg of pentachloroanisole and 2.89 µg of chlorinated compounds. Other unidentified metabolites were produced, some of them probably at high concentration. CONCLUSION Sorption is the principal mechanism used by Rhizopus oryzae CDBB‐H‐1877 to remove PCP from culture broth. However, a small fraction of sorbed PCP is degraded by means of methylation and dechlorination reactions. This biodegradation is mainly intracellular and depends on the carbon source. © 2014 Society of Chemical Industry