Title: Temperature effect on the degradation of phenol and catechol by Antarctic strain Lecanicillium sp. AL12

Biography:

Zlatka Alexieva has graduated in the specialty of biochemistry and microbiology from University of Sofia and has completed her PhD from Institute of Molecular Biology, Ukrainian Academy of Sciences at 1985. She has specialized in molecular biology in University of Baltimore, for one year. She was the Head of Division of General Microbiology and Head of Department of Microbial Genetics at the Institute of Microbiology, Bulgarian Academy of Sciences. She has published more than 120 scientific papers published in national and international journals and conference proceedings. The list of citations includes more than 700 citing publications.

Abstract

The ability of various microorganisms to decompose aromatic contaminants has been actively investigated for many years. However, there is very little available scientific information on Antarctic eukaryotic microorganisms and their industrial potential, although their presence there has long been established. The aim of the present study is to examine the ability of a fungal strain belonging to the genus Lecanicillium and isolated from a soil sample from Antarctica to degrade phenol and catechol in mesophilic conditions (23°C) and low temperature (10°C). The results show that the test strain degrades catechol in a higher concentration (0.3 g/l) than phenol (0.2 g/l) within about 400 hours. It was found that the activity of two key for degradation of phenolic compounds enzymes, such as phenol hydroxylase and catechol 1,2 - dioxygenase differ between the two temperature regimes, as at 10° C were lower. However, we observe that the time required for complete degradation of the two substrates does not differ significantly in the two temperature modes of cultivation. This effect may be due to the relatively low activity of phenol hydroxylase (lower than 0.1 U/mg proteins) with respect to both substrates at both test temperatures, resulting in an equally slow first decomposition step. The highest catechol 1, 2-dioxygenase activity was measured in the degradation of catechol at 23°C - 0.271 U/mg proteins, while at 10°C, it is 108 U/mg protein. These data indicate the ability of the test strain to degrade polyaromatic compounds where the catechol-1, 2-dioxinase enzyme activity is important.