• Title/Summary/Keyword: microbial ecology

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Impacts of Soil Microbial Populations on Soil Chemical and Biological Properties under Tropical Dry Evergreen Forest, Coromandel Coast, India

  • Sudhakaran, M.;Ramamoorthy, D.;Swamynathan, B.;Ramya, J.
    • Journal of Forest and Environmental Science
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    • v.30 no.4
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    • pp.370-377
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    • 2014
  • There are very few studies about soil chemical and biological properties under tropical dry evergreen forest Coromandel Coast, India. The present study was conducted in six tropical dry evergreen forests sites such as Oorani, Puthupet, Vadaagram, Kotthatai, Sendrakillai and Palvathunnan. We measured the quantity of soil chemical, biological properties and selected soil microorganisms for investigating the impacts of soil microbial populations on soil chemical and biological properties. The result showed that total N, P, Ca, S, Fe, Mn, Cu, Co, exchangeable K, Olson P, extractable Ca and phosphobacterial population were higher in the soil from Kothattai forest site. Organic carbon, total Mg, extractable Na, soil respiration, ${\beta}$-glucosidase activity, bacterial population, fungi population and actinomycetes population were higher in the soil from Palvathunn forest site. Total K, $NH_4{^+}$-N, $NO_3{^-}$-N, exchangeable K, extractable Ca, extractable Na, azotobacter population, bacillus population and rhizobacteria population were higher in the soil from Sendrakillai. Beijerinckia population, rhizobacteria and soluble sodium were higher in Puthupet forest soil. Total Si, total Na and exchangeable K were higher in soil from Oorani forest site. Total Mo and exchangeable K were higher in the soil from Vadaagaram forest site. The results showed that organic carbon, total N, $NH_4{^+}$-N, $NO_3{^-}$-N, extractable P, extractable Ca, soil respiration and ${\beta}$-glucosidase were significantly correlated with soil microbial populations. Therefore soil microorganisms are important factor for maintaining soil quality in tropical dry evergreen forest.

Influence of Mucor mucedo immobilized to corncob in remediation of pyrene contaminated agricultural soil

  • Hou, Wei;Zhang, Le;Li, Xiaojun;Gong, Zongqiang;Yang, Yongwei;Li, Zhi
    • Environmental Engineering Research
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    • v.20 no.2
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    • pp.149-154
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    • 2015
  • In recent years, immobilization agents were introduced into organic contaminated soil remediation and more and more materials were screened and used as the immobilizing carrier. However, effect of the decomposition of the immobilizing carrier on the bioremediation was rarely concerned. Therefore, the decomposition experiment of immobilizing carrier -corncob was carried out in the lab with the efficient degradation fungi - Mucor mucedo (MU) existing, and polycyclic aromatic hydrocarbons (PAHs) residues E4/E6 of the dissolved organic matter and microbial diversity during the decomposition process were studied. The results showed that: a) during the decomposition, the degradation of pyrene (Pyr) was mainly in the first 28 d in which the content of extractable Pyr decreased rapidly and the highest decrease was in the treatment with only MU added. b) Anslysis of E4/E6 changes showed that rich microorganisms could promote aromatization and condensation of humus. c) From the diversity index analysis it can also be seen that there is no significant difference in effects of PAHs on the uniformity of microorganisms. These results will not only be useful to have a better understanding of the bioavailability of contaminants adsorbed to biodegradable carriers in PAHs contaminated soil remediation, but also be helpful to perfect the principle of immobilized microbial technique.

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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    • v.26 no.9
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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.

Responses of Low-Quality Soil Microbial Community Structure and Activities to Application of a Mixed Material of Humic Acid, Biochar, and Super Absorbent Polymer

  • Li, Fangze;Men, Shuhui;Zhang, Shiwei;Huang, Juan;Puyang, Xuehua;Wu, Zhenqing;Huang, Zhanbin
    • Journal of Microbiology and Biotechnology
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    • v.30 no.9
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    • pp.1310-1320
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    • 2020
  • Low-quality soil for land reuse is a crucial problem in vegetation quality and especially to waste disposal sites in mining areas. It is necessary to find suitable materials to improve the soil quality and especially to increase soil microbial diversity and activity. In this study, pot experiments were conducted to investigate the effect of a mixed material of humic acid, super absorbent polymer and biochar on low-quality soil indexes and the microbial community response. The indexes included soil physicochemical properties and the corresponding plant growth. The results showed that the mixed material could improve chemical properties and physical structure of soil by increasing the bulk density, porosity, macro aggregate, and promote the mineralization of nutrient elements in soil. The best performance was achieved by adding 3 g·kg-1 super absorbent polymer, 3 g·kg-1 humic acid, and 10 g·kg-1 biochar to soil with plant total nitrogen, dry weight and height increased by 85.18%, 266.41% and 74.06%, respectively. Physicochemical properties caused changes in soil microbial diversity. Acidobacteria, Bacteroidetes, Chloroflexi, Cyanobacteria, Firmicutes, Nitrospirae, Planctomycetes, and Proteobacteria were significantly positively correlated with most of the physical, chemical and plant indicators. Actinobacteria and Armatimonadetes were significantly negatively correlated with most measurement factors. Therefore, this study can contribute to improving the understanding of low-quality soil and how it affects soil microbial functions and sustainability.

Bioinformatic Suggestions on MiSeq-Based Microbial Community Analysis

  • Unno, Tatsuya
    • Journal of Microbiology and Biotechnology
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    • v.25 no.6
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    • pp.765-770
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    • 2015
  • Recent sequencing technology development has revolutionized fields of microbial ecology. MiSeq-based microbial community analysis allows us to sequence more than a few hundred samples at a time, which is far more cost-effective than pyrosequencing. The approach, however, has not been preferably used owing to computational difficulties of processing huge amounts of data as well as known Illumina-derived artefact problems with amplicon sequencing. The choice of assembly software to take advantage of paired-end sequencing and methods to remove Illumina artefacts sequences are discussed. The protocol we suggest not only removed erroneous reads, but also dramatically reduced computational workload, which allows even a typical desktop computer to process a huge amount of sequence data generated with Illumina sequencers. We also developed a Web interface (http://biotech.jejunu.ac.kr/ ~abl/16s/) that allows users to conduct fastq-merging and mothur batch creation. The study presented here should provide technical advantages and supports in applying MiSeq-based microbial community analysis.

Use of Terminal Restriction Length Polymorphism (T-RFLP) Analysis to Evaluate Uncultivable Microbial Community Structure of Soil

  • Chauhan, Puneet Singh;Shagol, Charlotte C.;Yim, Woo-Jong;Tipayno, Sherlyn C.;Kim, Chang-Gi;Sa, Tong-Min
    • Korean Journal of Soil Science and Fertilizer
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    • v.44 no.1
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    • pp.127-145
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    • 2011
  • Various environmental ecosystems are valuable sources for microbial ecology studies, and their analyses using recently developed molecular ecological approaches have drawn significant attention within the scientific community. Changes in the microbial community structures due to various anthropogenic activities can be evaluated by various culture-independent methods e.g. ARISA, DGGE, SSCP, T-RFLP, clone library, pyrosequencing, etc. Direct amplification of total community DNA and amplification of most conserved region (16S rRNA) are common initial steps, followed by either fingerprinting or sequencing analysis. Fingerprinting methods are relatively quicker than sequencing analysis in evaluating the changes in the microbial community. Being an efficient, sensitive and time- and cost effective method, T-RFLP is regularly used by many researchers to access the microbial diversity. Among various fingerprinting methods T-RFLP became an important tool in studying the microbial community structure because of its sensitivity and reproducibility. In this present review, we will discuss the important developments in T-RFLP methodology to distinguish the total microbial diversity and community composition in the various ecosystems.