Introduction of green fluorescent protein gene into phenol-degrading Alcaligenes faecalis cells and their monitoring in phenol-contaminated soil

Alcaligenes faecalis (CCT 7145) was isolated from an Amazonian soil sample after an enrichment process to select for phenol-degrading microorganisms. The isolate was labeled with the green fluorescent protein (gfp) gene. The gfp-transformed cells were easily detected using a hand-held UV transillumi nator and their taxonomy was confirmed by 16S rRNA sequencing. Polymerase c hain reaction (PCR) and Southern blot analyses confirmed that the gfp gene was integrated into the chromosome. The addition of the gfp marker did not affect phenol degradation ability compared with the wild-type. Both, wild-t ype and gfp-marked A. faecalis cells encapsulated in alginate, tolerated 1, 700 mug ml(-1) phenol in liquid medium compared with 1,100 mug ml(-1) pheno l for free cells. C-14-Phenol mineralization in soil microcosms was also en hanced by inoculation with encapsulated cells. Survival of gfp-marked cells in phenol-contaminated soil over 22 days was determined from plate counts using, an epifluorescence microscope.