Journal of Biological Sciences1727-30481812-5719Asian Network for Scientific Information10.3923/jbs.2015.167.176IrshaidFawzi I.JacobJacob H.42015154Xylene is frequently released into the environment from biomass. As a consequence of this, its bioaccumulation can cause adverse health effects in humans. The purpose of this study was to screen for aerobic xylene-degrading bacteria from gasoline contaminated soil sites located around gas stations in the city of Al-Mafraq, Jordan. The effects of some physicochemical factors were examined. The 10 g of soil sample were transferred to Staniers mineral medium supplemented with 1% m-xylene and incubated at 30°C for 72 h. At least 4 aerobic m-xylene degrading isolates, designated as X1-X4 were identified using biochemical and molecular biology techniques. Isolates X1 and X2 were rod-shape Gram negative, oxidase and catalase positive bacteria. Isolate X3 was a rod-shape and Gram negative bacterium that was catalase positive and oxidase negative. Isolate X4 was a rod-shape, spore forming and Gram positive bacterium that was oxidase and catalase positive. Isolates X1, X2 and X4 showed high similarity to Pseudomonas aeruginosa, Pseudomonas stutzeri and Bacillus firmus, respectively, whereas X3 was a novel species of the genus Citrobacter, similar to Citrobacter amalonaticus. The growth rates of these isolates were slower at 2% m-xylene than at 1% m-xylene. The growth rate was less when the temperature was reduced from 30-25°C, whereas, at 45°C, the growth rate almost completely ceased. The growth rate was higher at pH 6.5 than at pH 5.5 or 8.5. The shortest generation times were found to be 8 h for Bacillus firmus, followed by 9 h for Pseudomonas stutzeri, 10 h for Citrobacter amalonaticus and 11 h for Pseudomonas aeruginosa under 1% m-xylene at 30°C and pH 6.8. In conclusion, we reported for the first time the isolation of four bacterial species with the ability to utilize m-xylene as a growth substrate.]]>Alrumman, S.A., D.B. Standing and G.I. Paton,2015273141Andrade, L.L., D.C. Leite, E.M. Ferreira, L.Q. Ferreira and G.R. Paula et al.,20122012Andreoni, V. and L. Gianfreda,200776287308Applegate, B.M., S.R. Kehrmeyer and G.S. Sayler,19986427302735Atlas, R.M. and T.C. Hazen,20114567096715Brusseau, M.L.,19981998pp: 81-98pp: 81-98Cappuccino, J. and N. Sherman,2008Das, K. and A.K. Mukherjee,2007Bacillus subtilis and Pseudomonas aeruginosa strains isolated from a petroleum-oil contaminated soil from North-East India.]]>9813391345Das, N. and P. Chandran,20112011Edwards, E.A. and D. Grbic-Galic,199460313322Evans, P.J., W. Ling, B. Goldschmidt, E.R. Ritter and L.Y. Young,199258496501Ghazali, F.M., R.N.Z.A. Rahman, A.B. Salleh and M. Basri,2004546167Hassanshahian, M., G. Emtiazi, R.K. Kermanshahi and S. Cappello,201019277291Higashioka, Y., H. Kojima and M. Fukui,2011110314322Jacob, J.H. and F.I. Irshaid,2012Citrobacter isolated from hypersaline environment.]]>7219226Jahn, M.K., S.B. Haderlein and R.U. Meckenstock,20057133553358Kandyala, R., S.P.C. Raghavendra and S.T. Rajasekharan,20101415Kao, C.M. and C.C. Wang,20003434133423Koch, A.L.,197038252259Leahy, J.G. and R.R. Colwell,199054305315Kovalick, Jr. W.W.,19922699106MacNaughton, S.J., J.R. Stephen, A.D. Venosa, G.A. Davis, Y.J. Chang and D.C. White,19996535663574Marshall, A.G. and R.P. Rodgers,20081051809018095Martinez, J.S., J.J.G. Sala, A.M. Vea and E.C. Casals,19898139140Nersesian, W., H. Booth, D. Hoxie, W. Hinckley and T. Shehata,1985548888Obst, M., A. Krug, H. Luftmann and A. Steinbuchel,2005Sedimentibacter hongkongensis strain KI and Citrobacter amalonaticus strain G isolated from an anaerobic bacterial consortium.]]>7136423652Otenio, M.H., M.T.L. da Silva, M.L.O. Marques, J.C. Roseiro and E.D. Bidoia,2005Pseudomonas putida CCMI 852.]]>36258261Solomon, F.E. and K. Viswalingam,2013417Sorkhoh, N.A., R.H. Al-Hasan, M. Khanafer and S.S. Radwan,199578194199Staats, M., M. Braster and W.F.M. Roling,20111312161227Stanier, R.Y., N.J. Palleroni and M. Doudoroff,196643159271Tamura, K. and M. Nei,199310512526Tamura, K., G. Stecher, D. Peterson, A. Filipski and S. Kumar,20133027252729Thamer, M., A.R. Al-Kubaisi, Z. Zahraw, H.A. Abdullah, I. Hindy and A. Abd Khadium,2013Bacillus thuringiensis, Northern of Iraq.]]>5865873Uchida, Y., H. Nakatsuka, H. Ukai, T. Watanabe and Y.T. Liu et al.,199364597605Van Hamme, J.D., A. Singh and O.P. Ward,200367503549Vidali, M.,20017311631172Vieira, P.A., R.B. Vieira, F.P. de Franc and V.L. Cardoso,20071405259Worsey, M.J. and P.A. Williams,1975Pseudomonas (putida (arvilla) mt-2: Evidence for a new function of the TOL plasmid.]]>124713Yakimov, M.M., G. Gentile, V. Bruni, S. Cappello, G. D'Auria, P.N. Golyshin and L. Giuliano,200449419432