The Evaluation of Bioremediation Potential of a Yeast Collection Isolated from Composting

Abstract

The influence of xenobiotic compounds on environment and on living organisms has been reported as an imminent public health problem. Among them we can list the contamination by Alkanes present in petroleum, hydrocarbons and organic contaminant substances from industrial effluents. Also, heavy metals are of particular interest because of their persistence in the environment contaminating the food webs. Among the innovative solutions for treatment of contaminated water and soil is the use of biological materials like living or dead microorganisms. Yeasts exhibit the ability to adapt to extreme condition such as temperature, pH and levels of organic and inorganic contaminants that make them a potential material to be used to remediate contaminated environment application. The goal of this work was to search for yeast isolates capable to use n-hexadecane (alkane hydrocarbon) as a primary carbon source and for those able to tolerate high concentration of lead (Pb) within a collection of 90 isolates obtained from the Sao Paulo Zoo composting system. The isolated yeast strains were identified by mass spectrometry (MALDI-TOF-MS) and by sequencing of the ribosomal DNA (18S and D1/D2) conserved regions. We found that the collection bares 23 isolates capable of utilizing n-hexadecane and one which is able to tolerate high concentration of lead (Pb) with a high biosorption index compared to the reference yeast strains (BY4742, PE-2, CAT-1 and BG-1). These results confirm the initial hypothesis that the Sao Paulo Zoo composting is the source for diverse yeasts species with biotechnological application poten tial.