Home About us MoEF Contact us Sitemap Tamil Website  
About Envis
Whats New
Microorganisms
Research on Microbes
Database
Bibliography
Publications
Library
E-Resources
Microbiology Experts
Events
Online Submission
Access Statistics

Site Visitors

blog tracking


 
Journal of Basic Microbiology
Vol. 52, No: 1, 2012, Pages: 53 - 65


Isolation and characterization of heavy-metal resistant microbes from roadside soil and phylloplane

Mohamed RM, Abo-Amer AE

Division of Microbiology, Department of Botany, Faculty of Science, Sohag University, Sohag, Egypt.

Abstract

Contamination by heavy metals is one of the major environmental problems in many countries and these contaminants reach from various sources such as traffic cars and other activities. Soil and phylloplane samples were collected from eight traffic and two non-traffic sites in Sohag city, Egypt. Heavy metal contents of CdČ+, ZnČ+ and PbČ+ of soil and phylloplane samples were determined and revealed high levels of ZnČ+ and PbČ+ in traffic samples. A total of 112 bacterial and 62 fungal isolates were obtained from soil and phylloplane. Bacterial isolates were characterized on the basis of morphological, physicochemical and biochemical characteristics; and 16S rRNA gene sequences. Fungal isolates were identified according to morphological characterization. Minimal inhibitory concentrations (MICs) of CdČ+, ZnČ+ and PbČ+ for each isolate were detected. All bacterial and fungal isolates demonstrated resistance to lead with MICs >0.528 mM and >0.211, respectively. Moreover, the maximum MICs of cadmium and zinc for bacteria were 0.821 mM and 1.471 mM, respectively, where as, MICs for fungi were 0.328 mM and 0.588 mM, respectively. The most resistant bacterial and fungal isolates were Pseudomonas aeruginosa RA65 and Penicillium corylophyllum, respectively. Therefore, P. aeruginosa RA65 was selected for further investigations. Growth curve study showed that 0.264 mM lead had no efficiently effect on the growth of P. aeruginosa RA65. Plasmid isolation evidenced by transformation studies indicated that P. aeruginosa RA65 harbored a single plasmid (~9.5 kb) which mediated heavy meal resistance. Consequently, these microbial isolates could be potentially used in bioremediation of heavy metal-contaminated environment.

Keywords:environmental problems,morphological, physicochemical and biochemical characteristics; and 16S rRNA gene sequences,heavy metal-contaminated environment.


 

 

 
Copyright © 2005 ENVIS Centre ! All rights reserved
This site is optimized for 1024 x 768 screen resolution