• Microbiology and Biotechnology Letters
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• v.40 no.2
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• pp.111-116
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• 2012

In this study, we investigated the microbial flora changes in Gugija-Liriope tuber Makgeolli during fermentation and storage periods. We brewed Gugija-Liriope tuber Makgeolli for a week through twostage fermentations and stored the fermentation broth for a month at $4^{\circ}C$ or $20^{\circ}C$. We collected the samples periodically and analyzed microbial flora changes using viable cell counts and PCR-denaturing gradient gel electrophoresis (DGGE). Yeast viable cells were seen to have decreased to 13% of pre-storage levels after storage for 15 days at $20^{\circ}C$; however significant changes were not observed during storage at $4^{\circ}C$. Prolongation of storage time dramatically decreased the availability of viable cells. Yeast viable cell numbers had decreased to 38% of pre-storage levels at $4^{\circ}C$ and 4.8% at $20^{\circ}C$ after storage for 30 days. The results of the DGGE profile for yeast showed that Saccharomyces cerevisiae and Saccharomyces sp. were the predominant strains at the beginning of fermentation and throughout the whole period of storage. Viable cell counts for total bacteria had decreased to 36% of pre-storage levels after storage for 15 days but did not significantly change for the full 30 days of storage at $4^{\circ}C$. Similarly, viable cell counts for bacteria had decreased to 5% while viable cell numbers did not significantly change for the full 30 days at $20^{\circ}C$. Viable cell counts for lactic acid bacteria were performed and the results were similar to those for total bacteria. The results of the DGGE profile for bacteria showed that Weissella cibaria was the predominant strain at the beginning of fermentation. However it had disappeared by the end of fermentation, and Lactobacillus fermentum and Pediococcus acidilactici became the predominant species during storage.

• Korean Journal of Environmental Agriculture
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• v.32 no.2
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• pp.148-154
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• 2013

BACKGROUND: Genetically modified(GM) trigonal cactus(Hylocereus trigonus Saff.) contained a coat protein gene of cactus virus X (CVX), which conferred resistance to the virus, phosphinothricin acetyltransferase (bar) gene, which conferred herbicide resistance, and a cauliflower mosaic virus 35S promoter (CaMV 35S). This study was conducted to evaluate the possible impact of GM trigonal cactus cultivation on the soil microbial community. METHODS AND RESULTS: Microorganisms were isolated from the rhizosphere of GM and non-GM trigonal cactus cultivation soils. The total numbers of bacteria, and actinomycete in the rhizosphere soils cultivated GM and non-GM trigonal cactus were similar to each other, and there was no significant difference. Dominant bacterial phyla in the rhizosphere soils cultivated with GM and non-GM trigonal cactus were Proteobacteria, Uncultured archaeon, and Uncultured bacterium. The denaturing gradient gel electrophoresis (DGGE) profiles show a similar patterns, significant difference was not observed in each other. DNA was isolated from soil cultivated GM and non-GM trigonal cactus, we analyzed the persistence of the inserted gene by PCR. Amplification of the inserted genes was not observed in the soil DNA, which was collected after harvest. CONCLUSION(S): This result suggests that the GM trigonal cactus cultivation does not change significantly the microbial community.

• Korean Journal of Food Science and Technology
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• v.46 no.1
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• pp.115-120
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• 2014

The purpose of this study was to develop a rice straw-derived Bacillus cereus (B. cereus)-free starter culture for traditional soybean fermented products using a B. cereus-specific bacteriophage, BCP8-2. To determine the optimal medium that supports the growth of rice straw-derived microorganisms and BCP8-2 activity, 5 different culture media were tested. The 5% ground bean (GB) medium was selected for further study. No B. cereus was detected in the BCP8-2-treated rice straw in GB medium, whereas B. cereus at a level of $10^7$ CFU/mL was recovered in the no-phage control. The total bacterial count reached approximately $10^9$ CFU/mL regardless of phage addition. When the 16S rRNA sequence-based microbial community was monitored using denaturing gradient gel electrophoresis (DGGE) and pyrosequencing, a similar microbial community was observed in the phage-treated and control samples. In conclusion, we demonstrate that phage can be used to prepare a rice straw-derived B. cereus-free starter culture with minimal effect on natural microflora.

• Korean Journal of Soil Science and Fertilizer
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• v.45 no.5
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• pp.829-835
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• 2012

The cultivation of genetically modified (GM) crops has increased due to their economic and agronomic advantages. Before commercialization of GM crops, however, we must assess the potential risks of GM crops on human health and environment. The aim of this study was to investigate the possible impact of Bt rice on the soil microbial community. Microbial communities were isolated from the rhizosphere soil cultivated with Bt rice and Nakdong, parental cultivar and were subjected to be analyzed using both culture-dependent and molecular methods. The total counts of bacteria, fungi, and actinomycetes in the rhizosphere of transgenic and conventional rice were not significantly different. Denaturing gradient gel electrophoresis (DGGE) analysis of PCR-amplified 16S rRNA genes revealed that the bacterial community structures during cultural periods were very similar each other. Analysis of dominant isolates in the rhizosphere cultivated with Bt and Nakdong rice showed that the dominant isolates from the soil of Bt rice and Nakdong belonged to the Proteobacteria, Cloroflexi, Actinobacteria, Firmicutes, and Acidobacteria. These results indicate that the Bt rice has no significant impact on the soil microbial communities during cultivation period. Further study remains to be investigated whether the residue of Bt rice effect on the soil environment.

• Korean Journal of Environmental Agriculture
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• v.29 no.3
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• pp.293-299
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• 2010

The aim of this study was to investigate the possible impact of Bt Chinese cabbage on the soil microbial community. Microbial communities were isolated from the rhizosphere of one Bt Chinese cabbage variety and four varieties of conventional ones and were subjected to be analyzed using both culture-dependent and molecular methods. The total counts of bacteria, fungi, and actinomycetes in the rhizosphere of transgenic and conventional Chinese cabbages were observed to have an insignificant difference. Denaturing gradient gel electrophoresis (DGGE) analysis of PCR-amplified 16S rRNA genes revealed that the bacterial community structures were very similar to each other and this genetic stability of microbial communities was maintained throughout the culture periods. Analysis of dominant isolates in the rhizosphere of transgenic and conventional Chinese cabbages showed that the dominant isolates from the soil of transgenic Chinese cabbage belonged to the Bacilli and Alphaproteobacteria, while the dominant isolates from the soil of conventional cabbage belonged to the Holophagae and Planctomycetacia, respectively. These results indicate that the Bt transgenic cabbage has no significant impact on the soil microbial communities.

• Asian-Australasian Journal of Animal Sciences
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• v.21 no.9
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• pp.1330-1338
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• 2008

This study was conducted to investigate the effects of Acanthopanax senticosus extract (ASE) as a dietary additive on gut microflora in weaned piglets. A total of sixty pigs were weaned at 21 d of age (BW = $5.64{\pm}0.23kg$) and allocated on the basis of BW and litter to three dietary treatments in a randomized complete block design. The dietary treatments were: control group (basal diet), antibiotics group (basal diet+0.02% colistin), and ASE group (basal diet+0.1% ASE). On d 7, 14 and 28 after consuming the experimental diets, five piglets per group were sacrificed and then the contents from the jejunum, ileum and cecum were collected to determine changes in the microbial community by using a polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) technique and estimating the contents of Lactobacillus and E. coli by in vitro culturing methods. The results showed that the ASE promoted the microflora diversity in the cecum. Enumeration of bacteria in the gut contents showed that the number of Lactobacillus increased (p<0.05), while that of E. coli decreased (p<0.05) when compared with the other 2 groups as the days of age progressed post-weaning. These findings suggested that the ASE, as a substitute for dietary antimicrobial products, could improve the development of the normal gut microflora and suppress bacterial pathogens, and effectively promote a healthy intestinal environment.

• Journal of Korean Society of Environmental Engineers
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• v.35 no.4
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• pp.294-300
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• 2013

In this study, major parameter of partial nitritation was investigated for the stable operation. In order to establish partial nitritation system, prevailing parameters such as temperature, BA (bicarbonate alkalinity) and pH were evaluated. As a result, it is inferred that appropriate bicarbonate alkalinity ratio (mg $NaHCO_3{\cdot}L^{-1}/mg$ Inf. $NH_4{^+}-N{\cdot}L^{-1}$) drives stable 50% partial nitritation at $32^{\circ}C$ and ambient temperature, respectively. Alkalinity ratio was proposed as new strategy for 50% partial nitritation without pH control in both temperature regimes. Because of the results, it was added amound of BA required only for 50% nitritation to inhibit nitratation. The effluent $NO_2{^-}-N/NH_4{^+}-N$ ratio reached almost 100% when initial bicarbonate alkalinity ratios (mg $NaHCO_3{\cdot}L^{-1}/mg$ Inf. $NH_4{^+}-N{\cdot}L^{-1}$) were 6.8 (R1) and 6.7 (R2), respectively. Polymerase chain reaction and denaturing gradient gel electrophoresis (PCR-DGGE) results demonstrated that AOB was the dominant nitrifying bacteria and NOB was negligible after adopting process control.

• Journal of Environmental Health Sciences
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• v.35 no.6
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• pp.517-525
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• 2009

The water quality of Lake Shihwa had been rapidly deteriorating since 1994 due to wastewater input from the watersheds, limited water circulation and the lack of a wastewater treatment policy. In 2000, the government decided to open the tidal embankment and make a comprehensive management plan to improve the water quality, especially inflowing stream water around Shihwa and Banwol industrial complex. However, the water quality and microbial community have not as yet been fully evaluated. The purpose of this study is to investigate the influent water quality around the industrial area based on chemical and biological analysis, and collected surface water sample from the Siheung Stream, up-stream to down-stream through the industrial complex, Samples were collected in July 2009. The results show that the downstream site near the industrial complex had higher concentrations of heavy metals (Cu, Mn, Fe, Mg, and Zn) and organic matter than upstream sites. A combination of DGGE (Denaturing Gradient Gel Electrophoresis) gels, lists of K-WQI (Korean Water Quality Index), cluster analysis, MDS (Multi-Dimensional Scaling) and PCA (Principal Component Analysis) has demonstrated clear clustering between Siheung stream 3 and 4 and with a high similarity and detected metal reducing bacteria (Shewanella spp.) and biodegrading bacteria (Acinetobacter spp.). These results suggest that use of both chemical and microbiological marker would be useful to fully evaluate the water quality.

• Asian-Australasian Journal of Animal Sciences
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• v.28 no.1
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• pp.50-57
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• 2015

This study was conducted to investigate the effect of soybean meal (SM) and soluble starch (SS) on biogenic amine production and microbial diversity using in vitro ruminal fermentation. Treatments comprised of incubation of 2 g of mixture (expressed as 10 parts) containing different ratios of SM to SS as: 0:0, 10:0, 7:3, 5:5, 3:7, or 0:10. In vitro ruminal fermentation parameters were determined at 0, 12, 24, and 48 h of incubation while the biogenic amine and microbial diversity were determined at 48 h of incubation. Treatment with highest proportion of SM had higher (p<0.05) gas production than those with higher proportions of SS. Samples with higher proportion of SS resulted in lower pH than those with higher proportion of SM after 48 h of incubation. The largest change in $NH_3$-N concentration from 0 to 48 h was observed on all SM while the smallest was observed on exclusive SS. Similarly, exclusive SS had the lowest $NH_3$-N concentration among all groups after 24 h of incubation. Increasing methane ($CH_4$) concentrations were observed with time, and $CH_4$ concentrations were higher (p<0.05) with greater proportions of SM than SS. Balanced proportion of SM and SS had the highest (p<0.05) total volatile fatty acid (TVFA) while propionate was found highest in higher proportion of SS. Moreover, biogenic amine (BA) was higher (p<0.05) in samples containing greater proportions of SM. Histamines, amine index and total amines were highest in exclusive SM followed in sequence mixtures with increasing proportion of SS (and lowered proportion of SM) at 48 h of incubation. Nine dominant bands were identified by denaturing gradient gel electrophoresis (DGGE) and their identity ranged from 87% to 100% which were mostly isolated from rumen and feces. Bands R2 (uncultured bacterium clone RB-5E1) and R4 (uncultured rumen bacterium clone L7A_C10) bands were found in samples with higher proportions of SM while R3 (uncultured Firmicutes bacterium clone NI_52), R7 (Selenomonas sp. MCB2), R8 (Selenomonas ruminantium gene) and R9 (Selenomonas ruminantium strain LongY6) were found in samples with higher proportions of SS. Different feed ratios affect rumen fermentation in terms of pH, $NH_3$-N, $CH_4$, BA, volatile fatty acid and other metabolite concentrations and microbial diversity. Balanced protein and carbohydrate ratios are needed for rumen fermentation.

• Journal of the Korea Organic Resources Recycling Association
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• v.24 no.4
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• pp.77-83
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• 2016

The objectives of this study was to investigate the difference between organic-farming and conventional-farming soils relatives to soil chemical properties and microbial flora. Fifteen soil sampling sites were chosen from the certified organic upland farm, considered with its location, crop and application of organic compost types. Soil chemical properties were analyzed by standard methods established by National Institute of Agricultural Sciences, Rural Development Administration. For the soil chemical properties, the values of pH were ranged from 4.5 to 7.3. The values of electrical conductivity (EC) in the sampling sites were below 2 dS/m of convention cultivation soil. For analyzing the microbial flora, the bacillus(16S rDNA) and cladothricosis(18S rDNA) were analyzed by using PCR-DGGE (Denaturing Gradient Gel Electrophoresis) in the soil of 15 sampling sites. Cluster analysis of biodiversity index was performed by using pattern of DGGE. DGGE patterns and clustering analysis of bacterial DNA from soil extracts revealed that the bacterial community was differentiated between less than 5 years and more than 5 years depending on the cultivation history. But there was no consistent tendency between cultivation history and regional trend in the case of molds. Therefore, it would be very effective to analyze bacterial clusters of organically cultivated soils in long - term cultivated soil for more than 5 years.