Characterization of sludge reduction and bacterial community dynamics in a pilot-scale multi-stage digester system with prolonged sludge retention time.

Sludge reduction performance and bacterial community dynamics in a pilot-scale multi-stage digester system with prolonged sludge retention time were characterized. Throughout the operation period of 281 days, the total loading sludge and the total digested sludge were 4700 and 3300 kg-MLSS. After 114 days of operation, the residual MLSS (RMLSS) in the reactors for sludge treatment was maintained at 18-25 kg-RMLSS m, and the sludge reduction efficiency achieved 95% under the F/M ratio (kg-loading MLSS kg-RMLSS) of less than 0.

Simultaneous mitigation of methane and odors in a biowindow using a pipe network.

In this study, a biowindow with a piped gas collection network is proposed as an area-efficient landfill gas treatment system. A 9-m biowindow was constructed for treating landfill gas collected from an area of 450 m in a sanitary landfill, and its performance was evaluated for 224 days. The methane removal efficiency was 59-100% at 146.

Tuning the Hydrophobicity of a Hydrogel Using Self-Assembled Domains of Polymer Cross-Linkers.

Hydrogels incorporated with hydrophobic motifs have received considerable attention to recapitulate the cellular microenvironments, specifically for the bio-mineralization of a 3D matrix. Introduction of hydrophobic molecules into a hydrogel often results in irregular arrangement of the motifs, and further phase separation of hydrophobic domains, but limited efforts have been made to resolve this challenge in developing the hydrophobically-modified hydrogel. Therefore, this study presents an advanced integrative strategy to incorporate hydrophobic domains regularly in a hydrogel using self-assembled domains formed with polymer cross-linkers, building blocks of a hydrogel.

Performance evaluation of an on-site biocomplex textile as an alternative daily cover in a sanitary landfill, South Korea.

The performance of a biocomplex textile prototype was evaluated as an alternative daily cover at an operational landfill site to mitigate odors and methane. The biocomplex textile prototype consisted of two layers of nonwoven fabric and biocarrier immobilized microorganisms and showed excellent removal of odors and methane compared to landfill cover soil. The complex odor intensity (odor dilution ratio (ODR)) on the surface of landfill cover soil was 1,000-10,000 ODR (average of 4,204 ODR), whereas it was 5-250 ODR (average of 55 ODR) on the surface of biocomplex textile.

Characterization of odor emissions and microbial community structure during degradation of pig carcasses using the soil burial-composting method.

A soil burial-composting method was proposed as a hybrid disposal method for infected carcasses. This is a modified soil burial technique that involves covering carcasses with compost to achieve a final compost bed of 1.0-1.

Odor mitigation and bacterial community dynamics in on-site biocovers at a sanitary landfill in South Korea.

Unpleasant odors emitted from landfills have been caused environmental and societal problems. For odor abatement, two pilot-scale biocovers were installed at a sanitary landfill site in South Korea. Biocovers PBC1 and PBC2 comprised a soil mixture with different ratios of earthworm casts as an inoculum source and were operated for 240 days.

Extended local similarity analysis (eLSA) reveals unique associations between bacterial community structure and odor emission during pig carcasses decomposition.

Soil burial and composting methods have been widely used for the disposal of pig carcasses. The relationship between bacterial community structure and odor emission was examined using extended local similarity analysis (eLSA) during the degradation of pig carcasses in soil and compost. In soil, Hyphomicrobium, Niastella, Rhodanobacter, Polaromonas, Dokdonella and Mesorhizobium were associated with the emission of sulfur-containing odors such as hydrogen sulfide, methyl mercaptan and dimethyl disulfide.

Biocomplex textile as an alternative daily cover for the simultaneous mitigation of methane and malodorous compounds.

Space-saving biocomplex textiles, which can be used as covers or rolled up as needed, have been demonstrated as alternative daily covers for the simultaneous mitigation of greenhouse gases (GHGs) and odors in landfills. The biocomplex textiles were made by inserting inorganic biocarriers (perlite (P), tobermolite (T) and their mixture (P/T)) between nonwoven fabrics. Methane (CH) and dimethyl sulfide (DMS) were used as model compounds for GHGs and odors, and a CH and DMS co-degrading microbial consortium was used as an inoculum source.

Seasonal characteristics of odor and methane mitigation and the bacterial community dynamics in an on-site biocover at a sanitary landfill.

Landfills are key anthropogenic emission sources for odors and methane. For simultaneous mitigation of odors and methane emitted from landfills, a pilot-scale biocover (soil:perlite:earthworm cast:compost, 6:2:1:1, v/v) was constructed at a sanitary landfill in South Korea, and the biocover performance and its bacterial community dynamics were monitored for 240 days. The removal efficiencies of odor and methane were evaluated to compare the odor dilution ratios or methane concentrations at the biocover surface and landfill soil cover surface where the biocover was not installed.

Characterization of Bacterial Community Dynamics during the Decomposition of Pig Carcasses in Simulated Soil Burial and Composting Systems.

Soil burial is the most widely used disposal method for infected pig carcasses, but composting has gained attention as an alternative disposal method because pig carcasses can be decomposed rapidly and safely by composting. To understand the pig carcass decomposition process in soil burial and by composting, pilot-scale test systems that simulated soil burial and composting were designed and constructed in the field. The envelope material samples were collected using special sampling devices without disturbance, and bacterial community dynamics were analyzed by high-throughput pyrosequencing for 340 days.

Chemical Structure of the Lipid A component of Pseudomonas sp. strain PAMC 28618 from Thawing Permafrost in Relation to Pathogenicity.

Climate change causes permafrost thawing, and we are confronted with the unpredictable risk of newly discovered permafrost microbes that have disease-causing capabilities. Here, we first characterized the detailed chemical structure of the lipid A moiety from a Pseudomonas species that was isolated from thawing arctic permafrost using MALDI-based mass spectrometric approaches (i.e.

Decolorization of acid, disperse and reactive dyes by Trametes versicolor CBR43.

The mycoremediation has been considered as a promising method for decolorizing dye wastewater. To explore new bioresource for mycoremediation, a new white-rot fungus that could decolorize various dyes commonly used in textile industries was isolated, and its ligninolytic enzyme activity and decolorization capacity were characterized. The isolated CBR43 was identified as Trametes versicolor based on the morphological properties of its fruit body and spores, as well as through partial 18S rDNA gene sequences.

Characterization of Dye Decolorization in Cell-Free Culture Broth of CBR43.

The dye decolorization rate in a cell-free culture broth of the white-rot fungus CBR43 was studied, including the effects of inhibitors of NaCl, Zn(II), and Cd(II) on dye decolorization activity. The maximum rates of dye decolorization in cell-free culture broth were 1,410, 44.7, 41.

MALDI-MS-based quantitative analysis for ketone containing homoserine lactones in Pseudomonas aeruginosa.

N-Acyl homoserine lactones (AHLs), quorum sensing molecules produced by Gram-negative bacteria, are used as important secondary metabolites for antibacterial drug development and cell-to-cell communication. Although various analytical techniques have been developed for detection and quantitation of AHLs from more complex bacterial culture media, only a few methods have been applied to AHL identification in physiological samples. Here, we developed a highly sensitive and reliable MALDI-based 3-oxo AHL quantitation method by employing Girard's reagent T (GT) to produce a permanent cationic charge state [M](+) at the ketone group of AHLs.

Biodegradation capacity utilization as a new index for evaluating biodegradation rate of methane.

Density of catalytic organisms can determine the biodegradation capacity and specific biodegradation rate (SBR). A new index, biodegradation capacity utilization (BCU, %), was developed for estimating the extent of actual biodegradation of a gas compound over the full capacity. Three methanotrophic cultures were serially diluted (1-1/25), and methane SBR and BCU were measured.

Characterization of a methane-oxidizing biofilm using microarray, and confocal microscopy with image and geostatic analyses.

A mixed methane-oxidizing biofilm was characterized, concurrently using a number of advanced techniques. Community analysis results by microarray exhibited that type II members dominated the methanotrophic community, in which Methylocystis was most abundant, followed by Methylosinus. Observation results by fluorescent in situ hybridization and confocal microscopy showed multiple biofilm colonies that were irregular, bell-shaped, with mean thickness of approximately 20 μm.

Effect of switching gas inlet position on the performance of a polyurethane biofilter under transient loading for the removal of benzene, toluene and xylene mixtures.

The performance of a polyurethane (PU) biofilter was evaluated using different operating modes (unidirectional flow (UF) and flow-directional switching (FDS) operations) under transient loading conditions (intermittent and shutdown). Gas mixtures containing benzene, toluene and xylene (BTX) were employed as model gases. Quantitative real-time PCR methods were used for targeting the tmoA gene responsible for BTX degradation and estimating density of the BTX-degraders in the PU filter bed.

Reduction of perchlorate by salt tolerant bacterial consortia.

Two perchlorate-reducing bacterial consortia (PRBC) were obtained by enrichment cultures from polluted marine sediments. Non-salt-tolerant PRBC (N-PRBC) was enriched without the addition of NaCl, and salt tolerant-PRBC (ST-PRBC) was enriched with 30 g-NaCl L(-1). Although the perchlorate reduction rates decreased with increasing NaCl concentration, ST-PRBC (resp.

Characterization of methane oxidation by a methanotroph isolated from a landfill cover soil, South Korea.

A methane-oxidizing bacterium was isolated from the enriched culture of a landfill cover soil. The closest relative of the isolate, designated M6, is Methylocystis sp. Based on a kinetic analysis, the maximum specific methane oxidation rate and saturation constant were 4.

Reduction of ammonia and volatile organic compounds from food waste-composting facilities using a novel anti-clogging biofilter system.

The performance of a pilot-scale anti-clogging biofilter system (ABS) was evaluated over a period of 125days for treating ammonia and volatile organic compounds emitted from a full-scale food waste-composting facility. The pilot-scale ABS was designed to intermittently and automatically remove excess biomass using an agitator. When the pressure drop in the polyurethane filter bed was increased to a set point (50 mm H(2)O m(-1)), due to excess biomass acclimation, the agitator automatically worked by the differential pressure switch, without biofilter shutdown.

Rhizoremediation of diesel-contaminated soil using the plant growth-promoting rhizobacterium Gordonia sp. S2RP-17.

A plant growth-promoting rhizobacterium (PGPR) was isolated and identified as Gordonia sp. S2RP-17, which showed ACC deaminase and siderophore synthesizing activities. Its maximum specific growth rate was 0.

Comparative studies on toluene removal and pressure drop in biofilters using different packing materials.

To select the best available packing material for malodorous organic gases such as toluene and benzene, biofilter performance was compared in biofilters employed different packing materials including porous ceramic (celite), Jeju scoria (lava), a mixture of granular activated carbon (GAC) and celite (GAC/celite), and cubic polyurethane foam (PU). A toluene-degrading bacterium, Stenotrophomonas maltophilia T3-c, was used as the inoculum. The maximum elimination capacities in the celite, lava, and GAC/celite biofilters were 100, 130, and 110 gm(-3) hr(-1), respectively.

Microbial treatment of high-strength perchlorate wastewater.

To treat wastewater containing high concentrations of perchlorate, a perchlorate reducing-bacterial consortium was obtained by enrichment culture grown on high-strength perchlorate (1200 mg L(-1)) feed medium, and was characterized in a sequence batch reactor (SBR) over a long-time operation. The consortium removed perchlorate in the SBR with high reduction rates (35-90 mg L(-1)h(-1)) and stable removal efficiency over 200-day operations. The maximum specific perchlorate reduction rate (qmax), half saturation constant (Ks), and optimal pH range were 0.

Plant growth-promoting trait of rhizobacteria isolated from soil contaminated with petroleum and heavy metals.

Three hundred and seventy-four rhizobacteria were isolated from the rhizosphere soil (RS) or rhizoplane (RP) of Echinochloa crus-galli, Carex leiorhyncha, Commelina communis, Persicaria lapathifolia, Carex kobomugi, and Equisetum arvense, grown in contaminated soil with petroleum and heavy metals. The isolates were screened for plant growth-promoting potential (PGPP), including indole acetic acid (IAA) productivity, 1-aminocyclopropane-1-carboxylic acid (ACC) deaminase activity, and siderophore(s) synthesis ability. IAA production was detected in 86 isolates (23.