Questions and anxieties to application of bioremediation to contaminating subsurface are as follows: accurate prediction of rehabilitation period, evidence of existence of contaminant－degrading microorganisms, information of growth of pathogen by supplement of nutrient to subsurface, and information of changing in microflora after bioremediation. To solve these queries, we performed development of novel simulation model to estimate completion of remediation work and DNA microarray for detection of tetrachloroethylene (PCE)－dehalogenating microorganisms. PCR－DGGE method was also applied to predict existence of kerosene－degrading bacteria and to monitor microflora change before and after bioremediation. Effect of pathogen on bioremediation was conducted using Escherichia coli as a model hygienic bacteria. These results are summarized.
Thermophilic nitrifying Bacillus sp. T3 which had been isolated from cattle manure composts was capable of growing on a defined media containing high concentrations of sodium chloride. The addition of the thermophilic nitrifying bacteria to composts is expected for mitigation of ammonia volatilization loss during composting. Based on the results from assimilation tests of coloration, antibiotics and carbon sources, a selective medium was devised for the thermophilic nitrifying Bacillus sp. T3. The composition of the medium was as follows : ammonium sulfate, 5.0 g; sorbitol,1.0 g; yeast extract, 0.5 g; dipotassium hydrogen phosphate, 3.1 g; sodium chloride, 20.0 g; erythrosin, 50.0 mg; polymyxin B sulfate, 10.0 mg; streptomycin, 4.0 mg; agar, 15.0 g; deionized water, 1,000 ml; pH 8.0. The selection of the thermophilic nitrifying Bacillus sp. T3 on the devised selective medium is effective for its culture at 50 ℃. The effects of adding the thermophilic nitrifying Bacilluss sp. T3 in composting and soil solarization were evaluated by using the devised selective medium.
To investigate fungi involving sclerotium formation, we collected sclerotia from forest soils of Mt. Ontake, Gifu prefecture, Japan, and created the clone-library of their ITS regions of rDNA. We also cultured fungi from those sclerotia, followed by identifying fungal species. The results of the clone-library analyses suggested that Cenococcum geophilum, a fungus known for sclerotium formation, was included in the isolated fungi, which were mostly ascomycetes. Although culturing C. geophilum was not successful, three dark septate endophytes (DSE), all of which were unidentified, formed sclerotia on the artificial medium. Therefore, the sclerotia examined in this study might have been formed by not only C. geophilum but also by other fungi.