Soils were inoculated

Nitrophenol degraded rapidly from flooded alluvial and pokkali (organic matter-rich acid sulfate) soils that were inoculated with parathion-enrichment culture containing 5-day-old cultures of Flavobacterium sp. ATCC 27551 and Pseudomonas sp. ATCC 29353 (Sudhaker-Barik and Sethunathan, 1978a). 4-Nitrophenol disappeared completely with the formation of nitrite, particularly in the inoculated soils rather than in the uninoculated soils. 

Based on the successful laboratory soil microcosm experiment, the most heavily contaminated soil was excavated from the surface (2 m) layerand treated ex situ. The soil was placed in an enclosed rectangular bed and its moisture content maintained at 15% (w/w). The soil was aerated with an agricultural spading machine. Surfactant, organic nutrients, and inorganic nutrients were applied to maintain an optimum C N P ratio (data not presented). The isolated microorganisms were inoculated into the soil as dilute suspensions on five separate occasions. 

Fungal Decay of Woods. Blocks of sweet gum and southern pine sapwood were inoculated with test fungi by the standard soil-block method (7). The test fungi were the brown rots Poria monticolla and Lentinus lepidius and the white rot Polyporus versicolor. As a control, one block of pine and one block of gum were left in the sterilized soil-block chambers in which the fungus had been started on feeder blocks and then sterilized. 

The bioremediation strategy used compost and composting materials mixed with the excavated soil in heaps known as biopiles. Two-parts contaminated soil were mixed with one-part inoculant that contained straw-compost, bark chips, lime (to adjust the pFl) and nutrients (supplied by a commercial fertilizer). The biopiles contained 7500 kg of material (volume of 13 m3) and were built on a layer of bark chips to provide insulation. The entire biopile was covered with a plastic sheet and moisture content was adjusted by watering. 

Inoculation of a sandy loam to nutrient broth and incubating for 4 days provided the mixed soil micro-flora source for 1 ml inoculation of the artificial medium. Thus 20 mg of test material was added to 20 ml of the medium in 50 ml flasks, which contained 5 g of a pancreatic digest of casein plus 1 g of dextrose per liter. After sterilization at 121° C for 15 min., the samples were inoculated with 1 ml of the soil micro-flora source and the headspace was flushed with oxygen. Controls consisted of samples tested indent-ically but containing no test material. 

Batch culture systems consisted of 125-mL Erlenmeyer flasks containing 50 mL MSM and 100 mg/L alachlor. The flasks were inoculated directly with 0.5 g of soil from simulated chemical spill experiments or with 1 mL aliquots of soil suspensions (1 g soil/10 mL H2O). The flasks were incubated on a rotary shaker at 25°C for up to 4 weeks with periodic sampling for microbial isolation. 

Fungal Decay of Woods. Blocks of NaOH-treated and untreated sugar maple were inoculated with three test fungi—a brown, a white, and a soft rot—by the standard soil-block method (8). At various intervals, the test blocks were removed, the fungal growth washed off, the block sterilized, and ovendried to obtain weight losses. 

Petri plates with agar media for specific types of microorganisms were inoculated with 8 individual droplets of 0.01 ml for each suspension (up to 2 suspensions per petri dish) and held for 6 days at 30°C in the dark before microorganisms were enumerated (number of positive droplets). The colony-forming units (CFU)/g root dry weight or soil dry weight were determined from tables provided by Harris and Sommers (1968). The smallest population of any microbial group that could be enumerated was 20 CFU/g of root or soil. 

For soil samples that had been inoculated with microorganisms 70 days after the addition of ferulic acid, recovery was reduced to less than 2% 30 days after soil samples were inoculated (for Cecil A soil samples 0, 4, and 20 p.g/g were recovered, respectively for Cecil B soil samples 0, 0.4, and 4 p.g/g were recovered, respectively). More of the ferulic acid recovered by neutral EDTA was available to soil microbes. This indicated that there was not only a quantitative difference but also a qualitative difference in the fractions of sorbed ferulic acid recovered by the two extraction procedures. By fractions I am referring to ferulic acids bound by different kinds and strengths of bonds to soil particles (see Section 2.4.3.2). 

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