Journal of Biotechnology & Biomaterials
Open Access

Abstract

Regulatory mechanisms involved in phenol catabolism in Rhodococcus erythropolis CCM2595 were analyzed. Th e pheA1+pheA2 genes (coding for subunits of phenol hydroxylase) were found to be regulated by the PheR activator and the genes of the catABC operon (catechol 1,2-dioxygenase, muconate cycloisomerase and muconolactone isomerase, respectively) were controlled by the CatR repressor. Expression of the pheA1+pheA2, pheR and catABC genes was induced by phenol. All promoters driving transcription of the genes within the pheA1A2-pheR-catR-catA-catB-catC cluster were localized and binding of PheR, CRP and PcaR regulators to the regulatory regions of the genes was proved by DNA-affi nity chromatography and mass spectrometry. Based on the results of expression analysis, R. erythropolis strains carrying modifi cations within the chromosome or on the plasmid vectors were constructed with the aim to improve phenol degradation. Strains carrying pheA1+pheA2, catABC and pheR on a multicopy R. erythropolis vector pSRK21 in various combinations and organization degraded phenol in laboratory minimal medium more effi ciently than the wild-type strain. Th e plasmid-harboring recombinant strains with the disrupted catR gene were up to 50% more effi cient than the wild-type strain in the bioremediation of wastewater medium based on effl uent from a chemical plant producing Bisphenol-A containing phenol (0.6 g/L). Th e plasmid constructs carrying all enzymecoding genes of the phenol degradation gene cluster were stably maintained in R. erythropolis cells during a 13-day cultivation in wastewater medium under nonselective conditions. Phenol degradation effi ciency of a consortium of various modifi ed R. erythropolis strains is being tested in fed-batch cultivations in phenolcontaining media.

Biography

Dr. Miroslav Pátek studied at the Institute of Chemical Technology in Prague, Czech Republic and completed his Ph.D. in 1988. He spent his working stay at the Institute of Biotechnology in Jülich, Germany in 1992-1994. Currently, he works as the head of the Department of Molecular Genetics of Bacteria at the Institute of Microbiology, Academy of Sciences of the Czech Republic in Prague. He published 50 research papers and book chapters and 6 patents. The main topic of his research is gene expression in Gram-positive bacteria of genera Corynebacterium and Rhodococcus, particularly in strains used for amino acid production and bioremediation.