Biodegradation of phenol by free and immobilized Candida tropicalis NPD1401

Abstract

The present research aimed to evaluate the free and immobilized cell of Candida tropicalis NPD1401 for phenol degradation. Immobilized cell of C. tropicalis degraded efficiently up to 98% at a concentration of 1000 mg/l of phenol whereas free cells degraded up to 63% of the same concentration under 9 days of incubation. Stored immobilized beads were reused after 15 days and found to have successfully degraded 62.1% of phenol in the mineral salt medium (MSM). Growth of C. tropicalis was observed in the phenol containing medium by measuring the dry weight of biomass (0.89 g/l at concentration 1000 mg/l) and the degradation was monitored using analytical techniques. Liquid chromatography-mass spectroscopy (LC-MS) analysis confirmed that phenol was degraded by ortho-pathways by the finding of metabolite cis, cis-muconic acid, phenyl phosphate and catechol. Next, isolated strain was identified on the basis of PCR amplification of sequence D2 region of the large subunit of 28S rDNA and it was confirmed as C. tropicalis. By observing the efficiency of the isolate it may be used for the further bioremediation purpose of the phenol contaminated site in the environments. Key words: Candida tropicalis, phenol, ortho-pathway, Cis-cis-muconic acid, immobilized cell.