• 제목/요약/키워드: Bacterial Community

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Bacterial Community of Galchi-Baechu Kimchi Based on Culture-Dependent and - Independent Investigation and Selection of Starter Candidates

  • Kim, Tao;Heo, Sojeong;Na, Hong-Eun;Lee, Gawon;Kim, Jong-Hoon;Kwak, Mi-Sun;Sung, Moon-Hee;Jeong, Do-Won
    • Journal of Microbiology and Biotechnology
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    • 제32권3호
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    • pp.341-347
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    • 2022
  • In this study, the bacterial community of galchi-baechu kimchi was determined using culture-based and culture-independent techniques (next generation sequencing:NGS), and showed discrepancies between results. Weissella koreensis and Pediococcus inopinatus were the dominant species according to the NGS results, while Bacillus species and P. inopinatus were dominant in the culture-dependent analysis. To identify safe starter candidates, sixty-five Bacillus strains isolated from galchi-baechu kimchi using culture-dependent methods were evaluated for their antibiotic resistance, presence of toxin genes, and hemolytic activity. Strains were then assessed for salt tolerance and protease and lipase activity. As a result, four strains-B. safensis GN5_10, B. subtilis GN5_19, B. velezensis GN5_25, and B. velezensis GT8-were selected as safe starter candidates for use in fermented foods.

Dynamics of Functional Genes and Bacterial Community during Bioremediation of Diesel-Contaminated Soil Amended with Compost

  • Hyoju Yang;Jiho Lee;Kyung-Suk Cho
    • Journal of Microbiology and Biotechnology
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    • 제33권4호
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    • pp.471-484
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    • 2023
  • Compost is widely used as an organic additive to improve the bioremediation of diesel-contaminated soil. In this study, the effects of compost amendment on the remediation performance, functional genes, and bacterial community are evaluated during the bioremediation of diesel-contaminated soils with various ratios of compost (0-20%, w/w). The study reveals that the diesel removal efficiency, soil enzyme (dehydrogenase and urease) activity, soil CH4 oxidation potential, and soil N2O reduction potential have a positive correlation with the compost amendment (p < 0.05). The ratios of denitrifying genes (nosZI, cnorB and qnorB) to 16S rRNA genes each show a positive correlation with compost amendment, whereas the ratio of the CH4-oxidizing gene (pmoA) to the 16S rRNA genes shows a negative correlation. Interestingly, the genera Acidibacter, Blastochloris, Erythrobacter, Hyphomicrobium, Marinobacter, Parvibaculum, Pseudoxanthomonas, and Terrimonas are strongly associated with diesel degradation, and have a strong positive correlation with soil CH4 oxidation potential. Meanwhile, the genera Atopostipes, Bacillus, Halomonas, Oblitimonas, Pusillimonas, Truepera, and Wenahouziangella are found to be strongly associated with soil N2O reduction potential. These results provide useful data for developing technologies that improve diesel removal efficiency while minimizing greenhouse gas emissions in the bioremediation process of diesel-contaminated soil.

조류성장에 따른 하수 박테리아 군집 변화에 관한 분자생태학적 연구 (Molecular Ecological Characterization of Wastewater Bacterial Communities in Response to Algal Growth)

  • 이주연;이장호;박준홍
    • 대한환경공학회지
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    • 제33권11호
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    • pp.847-854
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    • 2011
  • 주요 신재생에너지인 바이오에너지의 일환으로 조류를 이용한 바이오에너지 및 자원화 기술에 대한 관심이 높아지고 있다. 조류는 영양염류 제거 능력을 활용해서 하수와 같은 오폐수 내 난분해성오염물질과 영양염류 제거의 고도처리도 가능하다. 조류와 박테리아 간의 생태적인 상호작용이 조류를 활용한 하수처리 및 하수자원화에 중요한 역할을 함에도 불구하고, 실지 하수 조건에서 조류와 박테리아간의 생태학적인 상호작용에 관한 과학적인 정보가 부족하다. 본 연구에서는 하수에서 배양이 잘 되고, 지질함량이 높다고 알려진 국내 조류 종인 Ankistrodesmus gracilis SAG 278-2의 하수오염물질 제거 특성과 조류 주입에 따른 하수 박테리아 군집의 반응을 실지 하수 조건에서 연구하였다. 하수 박테리아의 수가 증가는 조류의 성장 속도를 감소시켰으나, 반면 조류의 성장은 박테리아의 생존 및 내성호흡 생분해 속도에는 영향을 주지 않았다. 조류가 주입된 하수에서 난분해성 유기물질 및 총질소의 제거 향상이 관찰되었다. 박테리아 16S rRNA 유전자 T-RFLP 분석에 따르면 조류의 주입은 시간에 따라 박테리아 군집에 영향을 주었다. 박테리아 16S rRNA 유전자 PCR 증폭, clone 및 염기서열 분석 결과, 하수 내 조류의 성장은 박테리아 군집 구성을 변화시키며, 조류와 함께 공동 성장 가능한 박테리아는 Sediminibacterium, Sphingobacterium, Mucilaginibacter 속에 속하는 개체로 판명되었다.

입상 활성탄 여과지에서 세균의 재성장과 생물막 형성 세균의 분리 및 동정 (Bacterial regrowth in biofilms formed in granular activated carbon filter adsorbers and the bacterial isolation and identification)

  • 이규철;권순복;이병기;박종근
    • 상하수도학회지
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    • 제22권2호
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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.

Diversity of Epiphytic and Acid-tolerant Epiphytic Bacterial Communities on Plant Leaves

  • Joung Pil-Mun;Shin Kwang-Soo;Lim Jong-Soon;Park Seong Joo
    • 한국미생물학회:학술대회논문집
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    • 한국미생물학회 2002년도 추계학술대회
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    • pp.100-105
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    • 2002
  • The diversity of epiphytic bacterial communities on deciduous oak tree (Quercus dentate Thunb.) leaves was examined both in the natural forest area with a clean air and in the industrial estate to assess effects of acidic deposition to the phyllosphere using 16S rDNA sequence data. In addition, acid-tolerant epiphytic bacterial communities were compared. A total of 78 epiphytic and 444 acid-tolerant clones were obtained from clone libraries, resulting in 20 and 17 phylotypes by analysis of restriction fragment length polymorphism (RFLP) for PCR-amplified 16S rDNA products. A low bacterial diversity in both areas was found. As tree leaves grow older, bacterial diversities were slightly increased in the level of subphylum. The community structure of epiphytic bacteria in both areas in April consisted of only two subphyla, $\beta-and\;\gamma-Proteobacteria$. In August two additional subphyla in both areas were found, but the composition was a little different, Acidobacteria and Cytophaga-Flexibacter-Bacteroids (CFB) group in the industrial estate and a -Proteobacteria and CFB group in the natural area, respectively. Acidobacteria could be an indicator of epiphytic bacteria for acidic deposition on plant leaves, whereas a -Proteobacteria be one of epiphytic bacteria that naturally survive on leaves that are not affected by acidic deposition. The acid-tolerant bacterial communities in April were composed of two subphyla, $\gamma-Proteobacteria$ and Low G+C gram-positive bacteria in both areas, and in August a-Proteobacteria was added to the community just in the natural forest area. The direct influence of acidic deposition on the acid-tolerant bacterial phylogenetic composition could not be detected in higher taxonomic levels such as subphylum, but at narrower or finer levels it could be observed by a detection of Xanthomonadales group of $\gamma-Proteobacteria$ just in the industrial estate.

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Investigation of Bacterial Diversity in Membrane Bioreactor and Conventional Activated Sludge Processes from Petroleum Refineries Using Phylogenetic and Statistical Approaches

  • Silva, Cynthia;Jesus, Ederson C.;Torres, Ana P. R.;Sousa, Maira P.;Santiago, Vania M. J.;Oliveira, Valeria M.
    • Journal of Microbiology and Biotechnology
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    • 제20권3호
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    • pp.447-459
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    • 2010
  • Bacterial diversity of two distinct wastewater treatment systems, conventional activated sludge (CAS) and membrane bioreactor (MBR), of petroleum refineries were investigated through 16S rRNA gene libraries. Sequencing and phylogenetic analysis showed that the bacterial community composition of sludge samples was distinct between the two wastewater treatment systems. MBR clones belonged predominantly to Class Betaproteobacteria, represented mainly by genera Thiobacillus and Thauera, whereas CAS clones were mostly related to Class Alphaproteobacteria, represented by uncultured bacteria related to Order Parvularculales. Richness estimators ACE and Chao revealed that the diversity observed in both libraries at the species level is an underestimate of the total bacterial diversity present in the environment and further sampling would yield an increased observed diversity. Shannon and Simpson diversity indices were different between the libraries and revealed greater bacterial diversity for the MBR library, considering an evolutionary distance of 0.03. LIBSHUFF analyses revealed that MBR and CAS communities were significantly different at the 95% confidence level ($P{\leq}0.05$) for distances $0{\leq}D{\leq}0.20$. This work described, qualitatively and quantitatively, the structure of bacterial communities in industrial-scale MBR and CAS processes of the wastewater treatment system from petroleum refineries and demonstrated clearly differentiated communities responsible for the stable performance of wastewater treatment plants.

Insights into the Gut Microbiota of Freshwater Shrimp and Its Associations with the Surrounding Microbiota and Environmental Factors

  • Zhao, Yanting;Duan, Cuilan;Zhang, Xu-xiang;Chen, Huangen;Ren, Hongqiang;Yin, Ying;Ye, Lin
    • Journal of Microbiology and Biotechnology
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    • 제28권6호
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    • pp.946-956
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    • 2018
  • The gut microbiota of aquatic animals plays a crucial role in host health through nutrient acquisition and outcompetition of pathogens. In this study, on the basis of the high-throughput sequencing of 16S rRNA gene amplicons, we examined the bacterial communities in the gut of freshwater shrimp (Macrobrachium nipponense) and in their living environments (sediment and pond water) and analyzed the effects of abiotic and biotic factors on the shrimp gut bacterial communities. High bacterial heterogeneity was observed in the freshwater shrimp gut samples, and the result indicated that both the surrounding bacterial community and water quality factors (particularly dissolved oxygen and temperature) could affect the shrimp gut bacterial community. Despite the observed heterogeneity, 57 genera, constituting 38-99% of the total genera in each of the 40 shrimp gut samples, were identified as the main bacterial population in the gut of M. nipponense. In addition, a high diversity and abundance of lactic acid bacteria (26 genera), which could play significant roles in the digestion process in shrimp, were observed in the shrimp gut samples. Overall, this study provides insights into the gut bacterial communities of freshwater shrimp and basic information for shrimp farming regarding the application of probiotics and disease prevention.

Redundancy Analysis Demonstration of the Relevance of Temperature to Ammonia-Oxidizing Bacterial Community Compositions in a Full-Scale Nitrifying Bioreactor Treating Saline Wastewater

  • Park, Hee-Deung;Lee, Seung-Yong;Hwang, Seok-Hwan
    • Journal of Microbiology and Biotechnology
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    • 제19권4호
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    • pp.346-350
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    • 2009
  • Although salt is known to influence the performance of nitrification significantly, it has not been well reported on how salt affects ammonia-oxidizing bacterial(AOB) community compositions and dynamics in wastewater treatment bioreactors. In this study, these questions were evaluated in a full-scale bioreactor treating saline wastewater. Clone library analysis for the ammonia monooxygenase subunit A gene revealed that AOB belonging to the Nitrosomonas europaea and the N. oligotropha lineages inhabited in the bioreactor. Terminal restriction fragment length polymorphism analysis for monthly samples demonstrated a fluctuation pattern among AOB populations, although AOB within the N. europaea lineage were dominant during the test period. Correlation analysis between patterns of terminal restriction fragments and environmental variables suggested that sodium, chloride, and sulfate were less important; rather, temperature was the most significant factor affecting the AOB community in the bioreactor.

A Method for Comparing Multiple Bacterial Community Structures from 16S rDNA Clone Library Sequences

  • Hur, Inae;Chun, Jongsik
    • Journal of Microbiology
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    • 제42권1호
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    • pp.9-13
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    • 2004
  • Culture-independent approaches, based on 16S rDNA sequences, are extensively used in modern microbial ecology. Sequencing of the clone library generated from environmental DNA has advantages over fingerprint-based methods, such as denaturing gradient gel electrophoresis, as it provides precise identification and quantification of the phylotypes present in samples. However, to date, no method exists for comparing multiple bacterial community structures using clone library sequences. In this study, an automated method to achieve this has been developed, by applying pair wise alignment, hierarchical clustering and principle component analysis. The method has been demonstrated to be successful in comparing samples from various environments. The program, named CommCluster, was written in JAVA, and is now freely available, at http://chunlab.snu.ac.kr/commcluster/.

Effects of Quorum Quenching on the Microbial Community of Biofilm in an Anoxic/Oxic MBR for Wastewater Treatment

  • Jo, Sung Jun;Kwon, Hyeokpil;Jeong, So-Yeon;Lee, Sang Hyun;Oh, Hyun-Suk;Yi, Taewoo;Lee, Chung-Hak;Kim, Tae Gwan
    • Journal of Microbiology and Biotechnology
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    • 제26권9호
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    • pp.1593-1604
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    • 2016
  • Recently, bacterial quorum quenching (QQ) has been proven to have potential as an innovative approach for biofouling control in membrane bioreactors (MBRs) for advanced wastewater treatment. Although information regarding the microbial community is crucial for the development of QQ strategies, little information exists on the microbial ecology in QQ-MBRs. In this study, the microbial communities of biofilm were investigated in relation to the effect of QQ on anoxic/oxic MBRs. Two laboratory-scale MBRs were operated with and without QQ-beads (QQ-bacteria entrapped in beads). The transmembrane pressure increase in the QQ-MBRs was delayed by approximately 100-110% compared with conventional- and vacant-MBRs (beads without QQ-bacteria) at 45 kPa. In terms of the microbial community, QQ gradually favored the development of a diverse and even community. QQ had an effect on both the bacterial composition and change rate of the bacterial composition. Proteobacteria and Bacteroidetes were the most dominant phyla in the biofilm, and the average relative composition of Proteobacteria was low in the QQ-MBR. Thiothrix sp. was the dominant bacterium in the biofilm. The relative composition of Thiothrix sp. was low in the QQ-MBR. These findings provide useful information that can inform the development of a new QQ strategy.