• Korean Journal of Microbiology
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• v.37 no.2
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• pp.124-129
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• 2001

For elucidating the effect of salinity to the effect of wastewater treatment, the heterotrophic bacterial numbers, total bacterial numbers, and the bacterial community structure by FISH method were analyzed. The total bacterial numbers were not significantly changed by the salinity. But the heterotrophic bacterial numbers and bacterial community structures were drastically changed by the increase of salinity. In case of 1% salinity, the heterotrophic bacterial numbers and structure were slightly changed comparing to those of contol. In case of 2% and higher salinities, the numbers of heterotrophic bacteria and the proportions of Eubacteria, Proteobacteria $\alpha$-group, $\rho$-group and Cytophaga-Flavobacterium groups were deceasing. By these results, the salinity stress to bacterial community in waste water treatment was unveiled, and for sustaining the waste water treatment system, the salinity should be lower than 1%.

• Korean Journal of Microbiology
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• v.27 no.4
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• pp.378-384
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• 1989

The numerical taxonomy of heterotrophic bacterial community in Lake Soyang was analysed. 95, 115, 88 and 75 strains which were isolated at each season from spring in 1987 to winter in 1988 were clustered by single matching coefficient. The diversity indices (H') were in the range of 0.511-1.684, and the community was most diverse in spring. THe seasonal variation of generic composition was significant. Of the domonant genera, Acinetobacter, Pseudomonas, and Flavobacterium were representative.

• Korean Journal of Microbiology
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• v.25 no.3
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• pp.229-237
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• 1987

To determine the characteristics of heterotrophic bacterial community in estuarine ecosystem, water and sediment samples were taden from Naktong estuary. All isolates were compared with 73 characters and described by cluster analysis. With same characters, 30 reference strains were able to divide into approximate species level at 80% similarity (S value). Diversity indices ($H^{1}$) of sediment column isolates were higher than water column isolates. The bacterial community commonly appeared in water and sediment column was reduced with going to downstream. Tolerance indices for temperature (Pt) and salinity (Ps) were also higher in sediment isolates than in water isolates. The bacterial community in sediment column is believed to be composed with diverse populations compared to water column and maintains its stability against various environmental changes with high physiological tolerances.

• Korean Journal of Microbiology
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• v.28 no.3
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• pp.204-209
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• 1990

The total and heterotrophic bacterial distributions, compositions and alkaline phosphatese actibities were analyzed in Lake Soyang from Sep. 1987 to Aug. 1988. The heterotrophic bacteria was small portion, 0.07-2.63% of total bacterial number which ranged from $3.2{\times}10^{5}$ to $3.2{\times}10^{6}$ cells/${\mu}\ell$. The composition of bacterial community was less diverse in summer and at the fish farm site and Peridinium blooming site. Pseudomonas and Flavo bacterium were the dominant genera in all sites. The highest proportion and activity of alkaline phsophatase was appeared in Flavobacterium, while Pseudomonas was the most predominant group.

• Journal of Korean Society of Water and Wastewater
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• v.22 no.2
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• pp.205-212
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• 2008

This study aimed to investigate the biofilm formation, bacterial regrowth, and bacterial community structure in the granular-activated carbon (GAC) filter adsorbers (FAs) used in water treatment plants. In 2005 and 2006, raw water, settled water, GAC FA by depth, and filtered water were collected twice a year from water treatment plants (WTPs) B and S. The number of heterotrophic bacteria, including mesophilic and psychrophilic bacteria, in such collected waters was investigated along with the total number of coliforms therein. Heterotrophic bacteria were detected in most samples, mainly at the surface layers of the GAC FAs, and fewer such bacteria were found in the lower and bottom layers. An increase in the bacterial number, however, was observed in the samples from various depths of the GAC FAs in WTPs B and S compared with the surface layers. An increase in the bacterial number was also detected in the filtered water. This may indicate that there is a regrowth of the bacteria in the GAC FA. Considering, however, that heterotrophic bacteria were not found in the filtered water, it can be deduced that most bacteria are removed in the chlorination process. Coliforms were detected at the surface layer of the GAC FAs, but their regrowth was not observed. MicroLog systems were used to identify the bacteria community distribution. Eight genera and 14 species, including Pseudomonas spp., were detected in WTP B, and 8 genera and 9 species, including Aeromonas spp., in WTP S. Further studies are required to elucidate their role in the biofilms in water treatment processes.

• Journal of Microbiology and Biotechnology
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• v.19 no.9
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• pp.858-868
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• 2009

The abundance, biomass, size distribution, and taxonomic composition of bacterial and protistan (heterotrophic and autotrophic nanoflagellates and ciliates) communities were investigated in six lakes of Masurian Lake District (north-eastern Poland) differing in trophic state. Samples were taken from the trophogenic water layer during summer stratification periods. Image analysis techniques with fluorescent in situ hybridization (FISH) as well as [$^3H$]-methyl-thymidine incorporation methods were applied to analyze differences in the composition and activity of bacterial communities. The greatest differences in trophic parameters were found between the humic lake and remaining non-humic ones. The same bacterial and heterotrophic nanoflagellate (HNF) cell size classes dominated in all the studied lakes. However, distinct increases in the contributions of large bacterial (>$1.0{\mu}m$) and HNF (>$10{\mu}m$) cells were observed in eutrophic lakes. The bacterial community was dominated by the ${\beta}$-Proteohacteria group, which accounted for 27% of total DAPI counts. Ciliate communities were largely composed of Oligotrichida. Positive correlations between bacteria and protists, as well as between nanoflagellates (both heterotrophic and autotrophic) and ciliates, suggest that concentrations of food sources may be important in determining the abundance of protists in the studied lakes.

• Journal of Microbiology and Biotechnology
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• v.18 no.11
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• pp.1826-1835
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• 2008

An autotrophic denitrification reactor (ADR-l) and a heterotrophic denitrification reactor (HDR-2) were operated to remove nitrate and nitrite in an anoxic environment in raw sewage. The $NO_3$-N removal rate of ADR-l was shown to range from 52.8% to 78.7%, which was higher than the $NO_3$-N removal rate of HDR-2. Specific denitrification rates (SDNR) of ADR-l and HDR-2 were 3.0 to 4.0 and 1.1 to $1.2\;mgNO_3$-N/gVSS/h, respectively. From results of restriction fragment length polymorphism (RFLP) of the 16S rRNA gene, Aquaspirillum metamorphum, Alcaligenes defragrans, and Azoarcus sp. were $\beta$-Proteobacteria that are affiliated with denitritying bacteria in the ADR-l. Specifically, Thiobacillus denitrificans was detected as an autotrophic denitrification bacteria. In HDR-2, the $\beta$-Proteobacteria such as Denitritying-Fe-oxidizing bacteria, Alcaligenes defragrans, Acidovorax sp., Azoarcus denitrificans, and Aquaspirillum metamorphum were the main bacteria related to denitrifying bacteria. The $\beta$-and $\alpha$-Proteobacteria were the important bacterial groups in ADR-l, whereas the $\beta$-Proteobacteria were the main bacterial group in HDR-2 based on results of fluorescent in situ hybridization (FISH). The number of Thiobacillus denitrificans increased in ADR-l during the operation period but not in HRD-2. Overall, the data presented here demonstrate that many heterotrophic denitritying bacteria coexisted with autotrophic denitrifying bacteria such as Thiobacillus denitrificans for nitrate removal in ADR-l. On the other hand, only heterotrophic denitritying bacteria were identified as dominant bacterial groups in HDR-2. Our research may provide a foundation for the complete nitrate removal in raw sewage of low-COD concentration under anoxic condition without any external organic carbon or the requirement of post-treatment.

• Journal of Microbiology and Biotechnology
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• v.13 no.2
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• pp.251-255
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• 2003

The bacterial compositions of seven hot-pepper sown soil were compared in this study. From the 624 isolates, 95 species and 49 genera were identified by fatty acid methyl ester analysis (FAME). The FAME results of seven soil showed two distinct clusters for aerobic and Gram-negative bacteria in the high productivity and monoculture soil samples. While Arthrobacter ($17\%$), Kocuria ($11\%$), Pseudomonas ($8\%$), and Bacillus ($8\%$) were predominant among bacteria which were cultured on heterotrophic (YG) agar medium, Pseudomonas ($56\%$), Stenotrophomonas ($16\%$), and Burkholderia ($8\%$) were predominant on crystal violet agar medium. Shannon Weaver indices (H) indicated that colonies obtained from heterotrophic agar medium (3.1) were found to be more diverse than those obtained from the crystal violet media (1.9). The results suggest that FAME analysis may be a potential indicator for of soil quality.

• Korean Journal of Environmental Biology
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• v.25 no.3
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• pp.273-278
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• 2007

The cell numbers of heterotrophic bacteria inhabiting the surface and bottom sea water harvested from the 5 stations in the marine ranching ground of Tongyeong coastal waters in $2003{\sim}2007$ were examined, and species composition of the heterotrophic bacterial population and dominant species were analyzed as well. Sea water samples collected in summer season contained much higher number of heterotrophic bacteria than those harvested in winter, spring and autumn seasons due to the higher sea water temperature. However the cell number of heterotrophic bacteria did not show a significant dependence on the location of the sampling stations. The cell number of heterotrophic bacteria in the surface sea water harvested in October 2003 and in September 2004 was not discernibly different from that in the bottom sea water and sometimes the former was even fewer than the latter because of the typhoon and localized torrential downpour. The number of heterotrophic bacteria decreased every year. The main bacterial species were Pseudomonas fluorescens TY1, Pseudomonas stutzeri TY2, Acinetobacter lwoffii TY3, Sphingomonas paucimobilis TY4, Burkholderia mallei TY5, Pasteurella haemolytica TY6, Pasteurella multocida TY7, Comamonas acidovorans TY8, Actinobacillus ureae TY9 and Chryseobacterium indologenes TY10. P. fluorescens TY1 and A. lwoffii TY3 were found to be the dominant species.

• Korean Journal of Microbiology
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• v.30 no.6
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• pp.444-449
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• 1992

A total of 858 heterotrohic bacteria were isolated and analyzed hy numerical method to investigate the heterotrophic hacterial community structure in Naktong Estuary. Although the values of H' (Shannon's diversity index). ranged between 1.54 and 3.49. were similar with those of the data hefore the construction of Naktong River barrage, however J' (evenness index. 0.31-0.80) was reduced. Physiological tolerance index for water temperature ($P_{s}$) was high at St.l and 2 whose depthes arc shallower than the other stations. and indices for pH ($P_{h}$) and salinity ($P_{s}$) were high at St. 2. 3. 4 where freshwater and seawater arc mixed. The predominant clusters were identified as Aeromonas. Vihrio. Pseudomonas. Acinelobacter-Morexella. Alcaligenes. Flavobacterium. Micrococcaccae. and Enterohacteriaceae. The kinds nf the isolates were similar with the previous result. hut the dominant genus was changed. These results suggest that the environmental changes in Naktong Estuary affect the hacterial physiological adaptation rather than the composition of heterotrophic hactcrial community.