ORIGINAL RESEARCH
Characterizing Microbial Populations
in Petroleum-Contaminated Soils
of Swat District, Pakistan
Muhammad Nazir Uddin1, Murtaza Ali1, Muhammad2, Muhammad Farooq2,
Nisar Ahmad1, Johar Jamil2, Kalsoom2, Muhammad Adnan3,
Nazish Shah4, Ahsan Khan4
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1Center for Biotechnology and Microbiology, University of Swat, Pakistan
2Department of Microbiology, University of Swabi, Pakistan
3Department of Agriculture, University of Swabi, Pakistan
4Department of Zoology, University of Swabi, Pakistan
Submission date: 2015-12-03
Final revision date: 2016-02-01
Acceptance date: 2016-02-02
Publication date: 2016-07-22
Pol. J. Environ. Stud. 2016;25(4):1721-1727
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ABSTRACT
Soil samples from petroleum-contaminated soil were collected from 25 different petroleum filling stations
and automobile workshops in the district of Swat, Khyber Pakhtunkhawa, Pakistan. A total of seven
bacterial genera were isolated. All of the isolates were Gram-positive bacteria. The genera identified by the
culture and cell morphological characteristics were: Bacillus, Streptococcus, Staphylococcus, Micrococcus,
Corynebacterium Arthrobacter, and Streptomyces. Lipolytic and saline activities of the selected isolates
were studied. Among the isolates, Arthrobacter, Staphylococcus, Bacillus, Micrococcus, Corynebacterium,
and Streptomyces produced lipase enzymes, while no lipase was produced by Streptococcus. Dense growth
of Bacillus and Streptococcus was observed at 1% NaCl. Dense growth of Streptomyces was observed at
strength of 2% NaCl. At 3% NaCl concentration, dense growth of Staphylococcus, Micrococcus, Corynebacterium,
and Arthrobacter was observed, indicating that they were moderately halotolerent. In our study,
Bacillus, Arthrobacter, and Streptomyces showed optimum growth at pH 8.0, and Streptococcus, Staphylococcus,
and Micrococcus showed optimum growth at pH 7.0. Only Corynebacterium showed optimum
growth at pH 9.0, indicating that it is tolerant of higher pH conditions.