ABSTRACT
I. INTRODUCTION The ability of microorganisms to degrade hydrocarbons was first described in 1895 by Miyoshi who reported on the microbial utilization of paraffins [1]. Shortly thereafter, the microbial consumption of methane has been described. However, for many years hydrocarbons were considered more or less biologically inert, and hydrocarbon-utilizing microorganisms were mainly of academic interest with little applicability other than in prospecting for oil and gas deposits, use in the fermentation industry, and for clean up of refinery effluents [2,3]. It was the Torrey Canyon accident in 1967 that aroused public concern about the ecological effects of oil pollution and focused scientific interest on the role of microorganisms in removing oil from the environment. In 1969, ZoBell [4] reported that more than 100 species of bacteria, yeasts, and fungi were capable of oxidizing hydrocarbons; however, most microbial species are limited to the kinds of hydrocarbons they can attack [5, 6]. Genetically engineered microorganisms can degrade a much wider spectrum of hydrocarbons [7]; however, the stability of such species in the natural environment is still unknown. This suggests that a group of microorganisms, rather than a single species, would be required to degrade crude oil.
