Summary-High molecular weight, linear polyacrylamide (PAM) with anionic charge is added to agricultural soils as an anti-erosion additive. Research indicates that soil microorganisms are able to utilize PAM as a source of N and that inorganic N pools are altered in some PAM-treated soils. The potential role of hydrdlytic amidase activity in the microbial utilization of PAM for N was investigated. Intracellular and extracellular amidase activity was measured over time in enrichment cultures which used PAM as sole N source. Enzyme activity increased concomitant with cell growth and N removal from PAM. Cell growth, N removal and amidase production were dependent upon readily-available C in the medium. Amidase activity and substrate specificity were determined for PAM-utilizing enrichment cultures exposed to various N sources. Polyacrylamide-specific amidase activity appears to be inducible, and not constitutive, based on the lack of amidase activity in cultures supplied with only ammonium nitrate for N versus substantial activity when PAM was added as an amendment with or without ammonium nitrate. Cultures amended with propionamide exhibited amidase activity largely specific for this small amide substrate, while cultures supplied with PAM as sole N source exhibited amidase activity specific for formamide, propionamide and PAM. Amidase activity and substrate specificity were determined for PAM-treated and untreated agricultural field soils. Polyacrylamide-specific amidase activity was higher in PAM-treated soil (14.86 ± 14.0 pg NH4 released soil) than in untreated soil (1.02 ± 2.3 pg NH4 released C I soil); activity specific for low molecular weight amides was slightly elevated or unchanged in PAM-treated soil as compared with untreated soil.

Summary-Linear polyacrylamide (PAM) is gaining considerable acceptance as an effective anti-erosion additive in irrigation water. The potential effects of repeated PAM application on soil microbial ecology and the potential for biotransformation of this polymer in soils are not completely known. Untreated and PAM-treated soils (coarse-silty, mixed, mesic Durixerollic Calciorthids) were collected from agricultural fields near Kimberly, ID. Soils were analyzed to determine the effects of PAM treatment on bacterial counts and inorganic N concentrations and the potential for PAM biotransformation. Culturable heterotrophic bacterial numbers were significantly elevated in PAM-treated soil for the plot planted to potatoes; this effect was not observed in the plot planted to dry pink beans. Total bacterial numbers, determined by AODC, were not altered by PAM treatment in any of the soils sampled. Polyacrylamide-treated soil planted to potatoes contained significantly higher concentrations of NO3 and NH 3 (36.7 ± 2.20 and 1.30 ± 0.3 mg kg-I , respectively) than did untreated soil (10.7 ± 2.30 and 0.50 ± 0.02 mg kg-I , respectively). For bean field soil there was no difference between treated and untreated soil inorganic N concentrations. Enrichment cultures generated from PAM-treated and untreated soils utilized PAM as sole N source, but not as sole C source. While the monomeric constituents of PAM, acrylamide and acrylic acid, both supported bacterial growth as sole C source, the PAM polymer did not. Enrichment cultures that used PAM for N exhibited amidase activity specific for PAM as well as smaller aliphatic amides. Utilization of PAM for N, but not for C, indicates that ultimately PAM may be converted into long chain polyacrylate, which may be further degraded by physical and biological mechanisms or be incorporated into organic matter. (0

"Capsule": Polyacrylamide preparations show promise in reducing flow of sediments, nutrients and microorganisms from animal production facilities. AbstractWaste streams associated with a variety of agricultural runoff sources are major contributors of nutrients, pesticides and enteric microorganisms to surface and ground waters. Water soluble anionic polyacrylamide (PAM) was found to be a highly effective erosion-preventing and infiltration-enhancing polymer, when applied at rates of 1-10 g m-3 in furrow irrigation water. Water flowing from PAM treated irrigation furrows show large reductions in sediment, nutrients and pesticides. Recently PAM and PAM + Ca0 and PAM + Al(SO4)3 mixtures have been shown to filter bacteria, fungi and nutrients from animal wastewater. Low concentrations of PAM [175-350 g PAM ha-' as PAM or as PAM + Ca0 and PAM + Al(SO 4) mixture] applied to the soil surface, resulted in dramatic decreases (10 fold) of total, coliform and fecal streptococci bacteria in cattle, fish and swine wastewater leachate and surface runoff. PAM treatment also filtered significant amounts of NH4, PO4 and total P in cattle and swine wastewater. This points to the potential of developing PAM as a water quality protection measure in combination with large-scale animal feeding operations. Potential benefits of PAM treatment of animal facility waste streams include: (1) low cost, (2) easy and quick application, (3) suitability for use with other pollution reduction techniques. Research on the efficacy of PAM for removal of protozoan parasites and viruses and more thorough assessment of PAM degradation in different soils is still needed to completely evaluate PAM treatment as an effective waste water treatment. We will present analysis and feasibility of using PAM, PAM + Al(SO4)3 , and PAM + CaO application for specific applications. Our results demonstrate their potential efficacy in reducing sediment, nutrients and microorganisms from animal production facility effluents. Published by Elsevier Science Ltd.

Polymerase chain reaction primers based on the ureC gene are described for use in detecting diverse groundwater ureahydrolyzing bacteria. Six degenerate primers were designed and evaluated for their ability to detect the gene encoding the large catalytic subunit of urease, ureC. Five combinations of these primers were tested pair-wise and displayed an overlapping detection range for bacterial isolates. Pair L2F/L2R exhibited the greatest detection range for described bacterial species and for bacterial isolates from groundwater samples belonging to the bacterial divisions Firmicutes, Actinobacteria, and the α, β, and γ subdivisions of Proteobacteria. Primers L2F/L2R exhibited a greater detection range than previously described ureC-specific primers, and amplified novel ureC sequences from groundwater isolates in the genera Hydrogenophaga, Acidovorax, Janthinobacterium, and Arthrobacter. A comparative phylogenetic analysis of ureC and 16S rRNA genes was performed to determine the utility of groundwater ureC sequence information as a phylogenetic marker for ureolytic species. Our results were consistent with previous analyses of urease genes which demonstrated that the ureC gene has undergone lateral transfer and is not a robust phylogenetic marker. However, the ureC-specific primers, L2F/L2R, demonstrate a broad detection range for ureolytic species, and can serve to enhance functional diversity analyses of ureolytic bacteria.

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