“Biomethanation of Syngas by Enriched Mixed Anaerobic Consortium in Pressurized agitated column”

Anoxic aquifers suffer from energy limitations due to the unavailability of organic substrates, as dictated by hydrogen (H2) for various electron-accepting processes. This deficiency often results in the accumulation of persistent organic pollutants, where bioremediation using organic compounds often leads to secondary contamination. This study involves the reductive dechlorination of pentachlorophenol (PCP) by dechlorinators that do not use H2 directly, but rather through a reduced state of humin—a solid-phase humic substance—as the extracellular electron donor, which requires an organic donor such as formate, lactate, etc. This shortcoming was addressed by the development of an anaerobic mixed culture that was capable of reductively dechlorinating PCP using humin under autotrophic conditions induced by homoacetogenesis. Here, H2 was used for carbon-dioxide fixation to acetate; the acetate produced was used for the reduction of humin; and consequently used for dechlorination through reduced humin. The 16SrRNA gene sequencing analysis showed Dehalobacter and Dehalobacterium as the possible dechlorinators, while Clostridium and Oxobacter were identified as the homoacetogens. Thus, this work contributes to the development of an anaerobic consortium that balanced H2 dependency, where efficiency of humin reduction extends the applicability of anaerobic microbial remediation in aquifers through autotrophy, syntrophy, and reductive dechlorination.

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Monitoring the development of anaerobic biofilms using fluorescent in situ hybridization and confocal laser scanning microscopy

Water Science & Technology ◽

10.2166/wst.2000.0243 ◽

2000 ◽

Vol 41 (12) ◽

pp. 69-77 ◽

Cited By ~ 18

Author(s):

J. C. Araujo ◽

G. Brucha ◽

J. R. Campos ◽

R. F. Vazoller

Keyword(s):

In Situ Hybridization ◽

Confocal Laser Scanning Microscopy ◽

Fluorescent In Situ Hybridization ◽

Laser Scanning ◽

Laser Scanning Microscopy ◽

Confocal Laser Scanning ◽

Scanning Microscopy ◽

Confocal Laser ◽

Anaerobic Consortium

In this study we investigated the development of anaerobic biofilm using a laboratory reactor. We were especially interested in comparing the organization of anaerobic cells (particularly those that are very common in domestic sewage sludge) in a hydrophilic (glass) versus a hydrophobic (polypropylene) surface. Fluorescent in situ hybridization (FISH) with domain and group specific probes directed against 16S ribosomal RNA were used to quantify microbial composition in the biofilm. FISH and confocal laser scanning microscopy (CLSM) were used to elucidate spatial distribution of microbes in the biofilms. Two experiments were carried out, one with pure methanogenic organisms and the other with a microbial anaerobic consortium. The pure methanogen cultures, Methanobacterium formicicum (DSM 1535); Methanosaeta concilli (DSM 3671) and Methanosarcina barkeri (DSM 800) were used to seed the modified Robbins Device (MRD) to allow the development of biofilms on polypropylene and glass surfaces during the 9-days experiment. The results showed that all the three species were colonizing both surfaces after two and nine days of experimental period. In another experiment, with polypropylene coupons only, MRD was seeded with a microbial anaerobic consortium and biofilm formation was studied during 11 days. At the end of this period, the biofilms generated were of uneven thickness with areas of minimal or no surface coverage and areas where the biofilm attained a thickness of 7.0 to 9.0 μm as revealed by CLSM. The results showed that the modified Robbins Device together with the fluorescent in situ hybridization and confocal laser scanning microscopy are suitable tools to study anaerobic biofilm development in different kinds of support materials.

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Degradation of benzoate by an anaerobic consortium and some properties of a hydrogenotrophic methanogen and sulfate-reducing bacterium in the consortium

Journal of Fermentation and Bioengineering ◽

10.1016/0922-338x(92)90163-o ◽

1992 ◽

Vol 73 (3) ◽

pp. 213-218 ◽

Cited By ~ 13

Author(s):

Yoichi Kamagata ◽

Nobuhisa Kitagawa ◽

Masaharu Tasaki ◽

Kazunori Nakamura ◽

Eiichi Mikami

Keyword(s):

Hydrogenotrophic Methanogen ◽

Sulfate Reducing ◽

Anaerobic Consortium

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Start-Up Procedures and Analysis of Microbial Segregation in HABR Using Synthetic Brewery Wastewater

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.113-116.1176 ◽

2010 ◽

Vol 113-116 ◽

pp. 1176-1181

Author(s):

Hui Ting Li ◽

Yong Feng Li ◽

Yan Jiao Gao ◽

Shu Ai Wang

Keyword(s):

Organic Loading ◽

Process Stability ◽

Treatment Efficiency ◽

Brewery Wastewater ◽

Loading Rates ◽

Start Up ◽

Anaerobic Consortium ◽

Removal Efficiencies ◽

Community Segregation ◽

High Treatment

A laboratory-scale hybrid anaerobic baffled reactor (HABR) with five compartments using synthetic brewery wastewater as organic loading rates (OLRs) was investigated for the start-up performance and the effects of microbial community segregation on reactor start-up. Experimental results demonstrated that it was found that the COD removal efficiencies were 92~96% at 1.2 kgCOD/(m3•d) feeding over a period of 33 d, after which the reactors then successfully started. The highest percentage of CO2 in biogas was found in Compartment 1, thereafter decreased from Compartment 2 to Compartment 5 which corresponded to the increased of the percentage of CH4. It indicated that the proper anaerobic consortium in each separate compartment was developed along with specific environmental conditions, which offers the explanations that high treatment efficiency of HABR accompanied by high process stability and low operational requirements in start-up period.

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Specific inhibitors for identifying pathways for methane production from carbon monoxide by a nonadapted anaerobic mixed culture

Canadian Journal of Microbiology ◽

10.1139/cjm-2013-0843 ◽

2014 ◽

Vol 60 (6) ◽

pp. 407-415 ◽

Cited By ~ 11

Author(s):

Silvia Sancho Navarro ◽

Ruxandra Cimpoia ◽

Guillaume Bruant ◽

Serge R. Guiot

Keyword(s):

Carbon Monoxide ◽

Metabolic Pathways ◽

Inhibitory Effect ◽

Gram Negative Bacteria ◽

Batch Tests ◽

Co Conversion ◽

Inhibitory Efficiency ◽

Anaerobic Consortium ◽

Specific Inhibitors ◽

Over Time

Specific inhibitors such as 2-bromoethanesulfonate (BES) and vancomycin were employed in activity batch tests to decipher metabolic pathways that are preferentially used by a mixed anaerobic consortium (sludge from an anaerobic digester) to transform carbon monoxide (CO) into methane (CH4). We first evaluated the inhibitory effect of both BES and vancomycin on the microbial community, as well as the efficiency and stability of vancomycin at 35 °C, over time. The activity tests with CO2–H2, CO, glucose, acetate, formate, propionate, butyrate, methanol, and ethanol showed that vancomycin does not inhibit some Gram-negative bacteria, and 50 mmol/L BES effectively blocks CH4production in the sludge. However, when sludge was incubated with propionate, butyrate, methanol, or ethanol as the sole energy and carbon source, methanogenesis was only partially inhibited by BES. Separate tests showed that 0.07 mmol/L vancomycin is enough to maintain its inhibitory efficiency and stability in the population for at least 32 days at 35 °C. Using the inhibitors above, it was demonstrated that CO conversion to CH4is an indirect, 2-step process, in which the CO is converted first to acetate and subsequently to CH4.

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