Abstract: In this paper, 24 naphthalene-degrading bacterial isolates were isolated respectively from wastewater treatment facility’s activated sludge and from petroleum wastewater. The total DNA of these isolates were extracted, and hybridized with several naphthalene-catabolic genes. The results indicated that the bacterial isolates isolated from the two sources were quite different in their contained naphthalene-degrading genes. The isolates from petroleum wastewater contained naphthalene dioxygenase Fe-S protein large subunit genenahAc, salicylaldehyde dehydrogenase gene nahF and its duplicate genenahV, salicylate hydroxylase genenahG and its duplicate gene nahU, catechol 2,3-dioxygenase gene nahH, catechol 1,2-dioxygenase gene catA, and naphthalene chemotaxis protein gene nahY, while those from activated sludge only contained nahAc, nahF, nahG and catA, but nonahY,nahV, nahU andnahH.

Key words: Hibernating generation, Microvelia horvathi, Hunger tolerance, Temperature, Density