Phenol resistant bacteria from soil: identification-characterization and genetical studies
2004
Ajaz, M. | Noor, N. | Rasool, S.A. | Khan, S.A.,Karachi Univ. (Pakistan). Dept. of Microbiology
Phenol and its derivatives are highly toxic and a source of serious environmental concern.The present study was undertaken to isolate and characterize the phenol resistant bacteriafrom indigenous soil (rhizosphere). Thirty soil bacterial isolates were identified and screenedfor phenol resistance. Four of these strains (belonging to genera Staphylococcus,Corynebacterium, Bacillus, and Proteus) were found resistant to 15 mM of phenol. Growthkinetic patterns and generation time of these phenol resistant strains were determined. Atextremely stressful conditions (glucose starved minimal medium with different molarities ofphenol) the generation time was considerably extended. However, Bacillus subtilis found anoptimum ON ratio in minimal medium with 0.1 mM phenol with a generation time of 174 minutes(several times shorter than the generation time of other sister resistant strains). Location ofphenol resistant genes was determined by acridine orange mediated plasmid curing.Interestingly, all the resistant isolates lost the characteristic (to resist phenol) after curingthereby indicating the plasmid genes being responsible for this property. Plasmid DNA isolatedfrom the uncured strains was transferred into the cured competent recipient cells. Stableintrageneric transfer of phenol resistance plasmid gene(s) was observed.
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