FACTORS INFLUENCING THE SURVIVAL AND ACTIVITY OF A PENTACHLOROPHENOL-DEGRADING Flavobacterium sp. IN SOIL SLURRIES

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Abstract
The effects of soil type, supplementation with carbon or inorganic nutrients, creosote, and copper/chromate/arsenate (CCA) mixtures, on viability and pentachlorophenol (PCP) degradation by inoculants of a PCP-degrading Flavobacterium sp. were examined in phosphate-buffered soil slurries. Populations of 108 Flavobacterium/mL in non-sterile slurries prepared with clay loam, silt loam, or loamy sand declined by at least 95% within 3 d. Populations were stable for at least a week in heat-sterilized clay loam slurries but addition of non-sterile soil resulted in rapid death of the Flavobacterium sp. Supplementation with 4 g L-1 Na-glutamate or glucose, promoted the growth of the Flavobacterium sp. in non-sterile clay loam slurries. Supplementation with 1 g L-1 Na-glutamate, glucose, or p-hydroxybenzoate stimulated PCP degradation when the Flavobacterium sp. was inoculated at .gtoreq. 108 cells mL-1 and the PCP concentration was less than 150 mg L-1. Addition of NH4+, SO42-, and Fe2+ together did not stimulate growth. Populations of culturable indigenous bacteria were larger in soil contaiing 50-300 mg L-1 PCP than in controls. Addition of PCP favored the predoinance of one colony type identified as a pseudomonad. Creosote of CCA mixtures, pollutants often found together with PCP contamination, were inhibitory to the Flavobacterium sp. in soil extract.