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

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 potential.

MALDI-TOF MS Assessment to Identify Environmental Mycobacteria

Over the past few decades, there has been a significant increase in the number of mycobacterial species described. Currently, the genus?Mycobacterium?consists of 170 species. Most species are called nontuberculous mycobacteria (NTM) and are potentially or rarely pathogenic and ubiquitous. One of the main challenges in mycobacteriology is the rapid and precise identification of these microorganisms. In this work, we compared two protein extraction protocols for the identification of 38 reference strains and clinical isolates, representing 27 species, by mass spectrometry (MALDI-TOF MS) to subsequently use the best method for identifying environmental mycobacteria. The results obtained with reference strains and clinical isolates showed that protocol A was effective in identifying 92.1% of mycobacterial specimens at the species level and protocol B, 50%. Therefore, protocol A was evaluated for the rapid identification of 27 environmental mycobacterial isolates. These isolates were subjected to PCR-restriction enzyme analysis (PRA-hsp65). Two isolates were misidentified by PRA-hsp65, whereas MALDI-TOF MS was able to identify them correctly. The results were confirmed by?hsp65 and 16S rRNA gene sequencing. Mass spectrometry has the advantage of being a simpler and faster technique than PRA-hsp65, and our results showed that MALDI-TOF MS is a valuable tool for the identification of environmental mycobacterial isolates.