Pyrene Biodegradation in Aqueous Solutions and Soil Slurries by Mycobacterium PYR-1 and Enriched Consortium

Soil contaminated with pyrene was treated by two different microbial systems, a pure strain of Mycobacterium sp. PYR-1 and a microbial consortium consisting of a Mycobacterium sp. and a mixed culture enriched from a petroleum-contaminated soil. Pyrene degradation was examined first in aqueous pyrene solutions and then in pre-equilibrated soil water slurry microcosms. The pure culture was found to degrade pyrene in the slurry faster than the consortium. Active pyrene degradation and cell growth were observed immediately in the systems with the pure culture, but in the consortium systems, a 10-d lay period was required before significant pyrene degradation and cell growth were observed. For dissolved pyrene, however, the specific biodegradation rates were similar in the two microbial systems.