• Journal of Korean Society of Water and Wastewater
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• v.20 no.3
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• pp.431-441
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• 2006

This study investigated the physiological characteristics of biofilm microorganisms formed onto the different drinking water distribution pipe surfaces. The simulated drinking water distribution pipe system which had several PVC, STS 304, and GS coupons was operated at flow velocity of 0.08 m/sec (Re 1,950) and 0.28 m/sec (Re 7,300), respectively. At velocity of 0.08 m/sec, the number of viable heterotrophic bacteria in the biofilm over the 3 months of operation averaged $3.3{\times}10^4$, $8.7{\times}10^4$, and $7.2{\times}10^3CFU/cm^2$ for PVC, STS, and GS surfaces, respectively. The number of attached heterotrophic bacteria averaged $1.4{\times}10^3$, $5.6{\times}10^2$, and $6.5{\times}10^2CFU/cm^2$ on PVC, STS, and GS surfaces at the system with relatively high flow velocity of 0.28m/sec. The changes of physiological profile of biofilm-forming microorganisms were characterized by community-level assay that utilized the Biolog GN microplates. Biofilms that formed on different pipe surfaces displayed distinctive patterns of community-level physiological profile (CLPP), which reflected the metabolic preference for different carbon sources and/or the utilization of these carbon sources to varying degrees. The CLPP patterns have shown that the metabolic potential of a biofilm community was different depending on the pipe material. The effect of the pipe material was also characterized differently by operation condition such as flow rate. At flow velocity of 0.08 m/sec, the metabolic potential of biofilm microorganisms on GS surface showed lower levels than PVC and STS biofilms. For biofilms on pipe material surfaces exposed to water flowing at 0.28 m/sec, the metabolic potential was in order of PVC>GS>STS. Generally, the levels of the bacterial biofilm's metabolic potentials were shown to be notably higher on pipe surfaces exposed to water at 0.08 m/sec when compared to those on pipe surfaces exposed to water at 0.28 m/sec.

• Korean Journal of Environmental Biology
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• v.26 no.1
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• pp.42-46
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• 2008

The community size of culturable heterotrophic bacteria and community level physiological profiles (CLPP) in the rhizosphere of Brassica rapa subsp. pekinensis (Chinese cabbage) were analyzed in two different sites. The average community size of culturable heterotrophic bacteria ranged between $2.65\times10^6CFU\;g^{-1}$ soil (Suwon) and $3.75\times10^6CFU\;g^{-1}$ soil (Yesan), whereas those of bulk soils ranged between $2.45\times10^6CFU\;g^{-1}$ soil (Suwon) and $2.97\times10^6CFU\;g^{-1}$ soil (Yesan). The average functional richness of Suwon rhizoshpere was 90.8, whereas that of Yesan rhizosphere was 154.1. High level of correlation was found between the community size and functional richness. The most actively utilized substrates in both rhizospheres were adonitol, L-asparagine, D-gluconic acid, L-glutamic acid and D-galacturonic acid. Clear differences were seen in the utilization patterns between the two sites. Differences were also observed for the patterns of bulk soils between the two sites, although D-raffinose and D-mannose were found as the commonly utilized substrates.

• Korean Journal of Environmental Agriculture
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• v.38 no.4
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• pp.219-224
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• 2019

BACKGROUND: Soil bacteria play important roles in organic matter decomposition and nutrient cycling during the non-growing season. The purpose of this study was to investigate the effects of soil management and chemical properties on the utilization of carbon sources by soil bacteria in paddy fields. METHODS AND RESULTS: The Biolog EcoPlate was used for analyzing community-level carbon substrate utilization profiles of soil bacteria. Soils were collected from the following three types of areas: plain, interface and mountain areas, which were tested to investigate the topology effect. The results of canonical correspondence analysis and Kendall rank correlation analysis showed that soil C/N ratio and NH₄⁺ influenced utilization of carbon sources by bacteria. The utilization of carbohydrates and complex carbon sources were positively correlated with NH₄⁺ concentration. Cultivated paddy fields were compared with adjacent abandoned fields to investigate the impact of cultivation cessation. The level of utilization of putrescine was lower in abandoned fields than in cultivated fields. Monoculture fields were compared with double cropping fields cultivated with barley to investigate the impact of winter crop cultivation. Cropping system altered bacterial use of carbon sources, as reflected by the enhanced utilization of 2-hydroxy benzoic acid under monoculture conditions. CONCLUSION: These results show that soil use intensity and topological characteristics have a minimal impact on soil bacterial functioning in relation to carbon substrate utilization. Moreover, soil chemical properties were found to be important factors determining the physiological profile of the soil bacterial community in paddy fields.

• Journal of Ecology and Environment
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• v.29 no.6
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• pp.551-558
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• 2006

Effects of Pb and $CO_2$ on soil microbial community associated with Pinus densiflora were investigated using community level physiological profiles (CLPP) and 16S rDNA PCR-denaturing gradient gel electrophoresis (DGGE) methods. Two-years pine trees were planted in Pb-contaminated soils and uncontaminated soils, and cultivated for 3 months in the growth chamber where $CO_2$ concentration was controlled at 380 or 760 ppmv. The structure of microbial community was analyzed in 6 kinds of soil samples (CA-0M : $CO_2$ 380 ppmv + Pb 0 mg/kg + initial, CB-0M : $CO_2$ 380 ppmv + Pb 500 mg/kg + initial, CA-3M : $CO_2$ 380 ppmv + Pb 0 mg/kg + after 3 months, CB-3M : $CO_2$ 380 ppmv + Pb 500 mglkg + after 3 months, EA-3M : $CO_2$ 760 ppmv + Pb 0 mg/kg + after 3 months, EB-3M : $CO_2$ 760 ppmv + Pb 500 mg/kg + after 3 months). After 3 months, the substrate utilization in the uncontaminated soil samples (CA-3M vs EA-3M) was not significantly influenced by $CO_2$ concentrations. However, the substrate utilization in the Pb-contaminated soil samples (CB-3M vs EB-3M) was enhanced by the elevated $CO_2$ concentrations. The results of principal component analysis based on substrate utilization activities showed that the structure of microbial community structure in each soil sample was grouped by Pb-contamination. The similarities of DGGE fingerprints were 56.3 % between the uncontaminated soil samples (CA-3M vs EA-3M), and 71.4% between the Pb-contaminated soil samples (CB-3M vs. EB-3M). The similarities between the soil samples under $CO_2$ 380 ppmv (CA-3M vs CB-3M) and $CO_2$, 760 ppmv (EA-3M vs EB-3M) were 53.3% and 35.8%, respectively. These results suggested that the structure of microbial community associated with Pinus densiflora were sensitively specialized by Pb-contamination rather than $CO_2$ concentration.