NONSELECTIVE PRECULTIVATION OF BACTERIA ABLE TO DEGRADE DIFFERENT POLYCYCLIC AROMATIC-HYDROCARBONS (PAH)

The influence of the precultivation with different carbon sources on t he ability of three different bacterial strains (Sphingomonas sp. stra in BA2, Gordona sp. strain BP9, Mycobacterium sp. strain VF1) to grow on phenanthrene, anthracene, pyrene or fluoranthene as the sole source of carbon and energy were studied. The strains were found to maintain their ability to grow on two of the four PAH after 30 serial transfer s in liquid nutrient broth medium without selective pressure. The abil ity to grow on these PAH as the sole carbon and energy source was also maintained after curing experiments with acridine orange. The high st ability of the PAH-degradation phenotype suggests that the tested stra ins early at least parts of the PAH-degradation pathway genes on the c hromosome. The PAH-degradation versatility of the strains was also inf luenced by the carbon source being used for precultivation. Possible r easons for the particularly good impact of the precultivation on hexad ecane on the PAH degradation are discussed in this paper.