HYDROCARBON-DEGRADING BACTERIA AT OIL-SPRINGS, TEXAS

Hydrocarbon degrading bacteria capable of heterotrophic growth in air were isolated from the oily mousse (biodegraded oil) from two separate sites at Oil Springs in east Texas. This is an area of long-standing crude oil seepage into a freshwater system. Of the four species of bac teria isolated from one site, and the five from the other, only two sp ecies were common to the oil at both sites. The isolates of these comm on species, however, were biotypically different from each other. Samp les from both sites contained strains capable of growth on crude oil a s a sole source of carbon (unconditional strains) along with strains t hat could degrade oil if proteose peptone was available in the growth medium (conditional strains). Additionally, the groups of isolates as a whole from each sample displayed remarkable similarities in the size s of extrachromosomal elements, adhesion to crude oil, and hydrocarbon substrate utilization. The results indicate that common selection pre ssures may have produced groups of bacteria of different genera with s imilar physiologies at both sites.