Characterization of Phenol Biodegradation by Comamonas testosteroni ZD4-1 and Pseudomonas aeruginosa ZD4-3

Key words: 
• Aromatic compounds /
• Phenol /
• Biodegradation /
• Ortho-pathways /
• Meta-pathways /
• C120 /
• C230

Abstract: Objective To investigate the characteristic and biochemical mechanism about the phenolbiodegradation by bacterial strains ZD 4-1 and ZD 4-3. Methods Bacterial strains ZD 4-1 and ZD4-3 were isolated by using phenol as the sole source of carbon and energy, and identified by 16SrDNA sequence analysis. The concentrations of phenol and total organic carbon (TOC) weremonitored to explore the degradation mechanism. The biodegradation intermediates were scanned at375 nm by using a uv-vis spectrophotometer. The enzyme assays were performed to detect theactivities of dioxygenases. Results Bacterial strains ZD 4-1 and ZD 4-3 were identified asComamonas testosteroni and Pseudomonas aeruginosa by 16S rDNA sequence analysis, respectively.The growth of the two strains was observed on a variety of aromatic hydrocarbons. The strains ZD 4-1and ZD 4-3 metabolized phenol via ortho-pathways and meta-pathways, respectively. In addition, theresults of enzyme assays showed that the biodegradation efficiency of phenol by meta-pathways washigher than that by ortho-pathways. Finally, the results of induction experiment indicated that thecatechol dioxygenases, both catechol 1,2-dioxygenase (C120) and catechol 2,3-dioxygenase (C230),were all inducible. Conclusion The strains ZD 4-1 and ZD 4-3 metabolize phenol throughortho-pathways and meta-pathway, respectively. Furthermore, the biodegradation efficiency of phenolby meta-pathways is higher than that by ortho-pathways.