Degradation of Phenol by Candida Tropicalis Sp.: Kinetics, Identification of Putative Genes and Reconstruction of Catabolic Pathways by Genomic and Transcriptomic Characteristics

Abstract

Candida tropicalis sp. was isolated with predominant biodegradation capability to phenol compounds, even with high concentration or in acid environment. Results indicated that under the wide concentration of 10–1750 mg/L, the strain exhibited well degradation efficiency and maximum specific growth rate, with degradation rates of 0.660 1/h and 0.47 mg/ (mg h), respectively. Differentially expressed genes were screened out, and results revealed a complete process of energy and carbon metabolism. The genes' arrangements and phylogenetic information showed the unique genetic characteristics of the strain. Catabolic pathways were reconstructed and some key phenol-degrading genes were obviously upregulated, including pheA, catA, OXCT and fadA. A notable detail that CMBL encoding carboxymethylenebutenolidase was speculated to be involved in a shortened pathway of phenol degradation, thereby contributing to the reconstruction of the novel phenol catabolic pathway through the hydrolases of dienelactone. Finally, key enzymes were verified.

Keywords: Phenol, Candida tropicalis, Kinetics, Functional genes, Catabolic pathway