Heterotrophic Bacteria Production and Microbial Community Assessment

The success of a recirculating aquaculture system (RAS) greatly depends on the structure, dynamics and activities of microbial community. Heterotrophic bacteria as the major members play various roles. The heterotrophic bacterial community structure in threestaged biofilters was studied using four different media. 228 isolates belonging to 77species were obtained and affiliated toGammaproteobacteria,Alphaproteobacteria,Bacteroidetes,Firmicutes,ActinobacteriaandBetaproteobacteria.Gammaproteobacteriawas the predominant group. The concurrence was found between potential pathogens (VibrioandShewanella) and probiotics (BacillusandPseudomonas). On the basis of community diversity index, we could infer that differences existed between stages, and the diversity index increased along the biofilters. A comprehensive understanding of microbial community in RAS will be in favor of utilization of microbial resources and optimizing the culture systems' operation.

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Assessing arsenic bioremediation potential of epilithic biofilms affected by acid-mine drainage

10.5194/biofilms9-81 ◽

2020 ◽

Author(s):

Sarah Zecchin ◽

Nicoletta Guerrieri ◽

Evelien Jongepier ◽

Leonardo Scaglioni ◽

Gigliola Borgonovo ◽

...

Keyword(s):

Microbial Community ◽

Acid Mine Drainage ◽

Mine Drainage ◽

Heterotrophic Bacteria ◽

16S Rrna Genes ◽

Rrna Genes ◽

Sampling Point ◽

Epilithic Biofilm ◽

Acid Mine ◽

Epilithic Biofilms

Arsenic is a toxic but naturally abundant metalloid that globally leads to contamination in groundwater and soil, exposing millions of people to cancer and other arsenic-related diseases. In several areas in Northern Italy arsenic in soil and water exceeds law limits (20 mg kg-1 and 10 mg L-1, respectively), due to both the mineralogy of bedrock and former mining activities. The Rio Rosso stream, located in the Anzasca Valley (Piedmont) is heavily affected by an acid mine drainage originated from an abandoned gold mine. Arsenic, together with other heavy metals, is transferred by the stream to the surrounding area. The stream is characterized by the presence of an extensive reddish epilithic biofilm at the opening of the mine and on the whole contaminated waterbed. The aim of this study was to characterize the mechanisms allowing the biotic fraction of this biofilm to cope with extreme arsenic concentrations. The composition and functionality of the microbial communities constituting the epilithic biofilms sampled in the close proximity and downstream the mine were unraveled by 16S rRNA genes and shotgun Illumina sequencing in relation to the extreme physico-chemical parameters. In parallel, autotrophic and heterotrophic microbial populations were characterized in vivo by enrichment cultivation and isolated strains were tested for their ability to perform arsenic redox transformation. Preliminary analyses indicated that the biofilm accumulated arsenic in the order of 6 &#183; 103 mg kg-1, in contrast to 0.14 mg L-1, measured in the surrounding water. The main chemical parameter affecting the composition of the microbial community was the pH, being 2 next to the mine and 6.7 in the downstream sampling point. In both sampling sites iron- and sulfur-cycling microorganisms were retrieved by both cultivation and molecular methods. However, the diversity of the microbial community living next to the mine was significantly lower with respect to the community developed downstream. In the latter, autotrophic Cyanobacteria belonging to the species Tychonema were the dominant taxa. A complete arsenic cycle was shown to occur, with heterotrophic bacteria mainly responsible for arsenate reduction and autotrophic bacteria performing arsenite &#160;oxidation. These observations indicate that the epilithic biofilm living in the Rio Rosso stream represents a peculiar ecosystem where microorganisms cope with metalloid toxicity likely using diverse mechanisms. Such microbial metabolic properties might be exploited in bioremediation strategies applied in arsenic-contaminated environments.

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Kinetic modelling and microbial community assessment of anaerobic biphasic fixed film bioreactor treating distillery spent wash

Water Research ◽

10.1016/j.watres.2011.05.048 ◽

2011 ◽

Vol 45 (14) ◽

pp. 4248-4259 ◽

Cited By ~ 40

Author(s):

Bhavik K. Acharya ◽

Hilor Pathak ◽

Sarayu Mohana ◽

Yogesh Shouche ◽

Vasdev Singh ◽

...

Keyword(s):

Microbial Community ◽

Kinetic Modelling ◽

Community Assessment ◽

Spent Wash ◽

Distillery Spent Wash ◽

Fixed Film ◽

Fixed Film Bioreactor

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Microbial dynamics in a High-Arctic glacier forefield: a combined field, laboratory, and modelling approach

10.5194/bg-2016-52 ◽

2016 ◽

Author(s):

James A. Bradley ◽

Sandra Arndt ◽

Marie Šabacká ◽

Liane G. Benning ◽

Gary L. Barker ◽

...

Keyword(s):

Microbial Community ◽

Numerical Model ◽

Microbial Communities ◽

Community Dynamics ◽

Heterotrophic Bacteria ◽

High Arctic ◽

Soil Development ◽

Arctic Soils ◽

Field Laboratory ◽

Modelling Approach

Abstract. Modelling the development of soils in glacier forefields is necessary in order to assess how microbial and geochemical processes interact and shape soil development in response to glacier retreat. Furthermore, such models can help us predict microbial growth and the fate of Arctic soils in an increasingly ice-free future. Here, for the first time, we combined field sampling with laboratory analyses and numerical modelling to investigate microbial community dynamics in oligotrophic proglacial soils in Svalbard. We measured low bacterial growth rates and growth efficiencies (relative to estimates from Alpine glacier forefields), and high sensitivity to soil temperature (relative to temperate soils). We used these laboratory measurements to inform parameter values in a new numerical model and significantly refined predictions of microbial and biogeochemical dynamics of soil development over a period of roughly 120 years. The model predicted the observed accumulation of autotrophic and heterotrophic biomass. Genomic data indicated that initial microbial communities were dominated by bacteria derived from the subglacial environment, whereas older soils hosted a mixed community of autotrophic and heterotrophic bacteria. This finding was validated by the numerical model, which showed that active microbial communities play key roles in fixing and recycling carbon and nutrients. We also demonstrated the role of allochthonous carbon and microbial necromass in sustaining a pool of organic material, despite high heterotrophic activity in older soils. This combined field, laboratory and modelling approach demonstrates the value of integrated model-data studies to understand and quantify the functioning of the microbial community in an emerging High-Arctic soil ecosystem.

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Ecological and molecular characterization of a coral black band disease outbreak in the Red Sea during a bleaching event

PeerJ ◽

10.7717/peerj.5169 ◽

2018 ◽

Vol 6 ◽

pp. e5169 ◽

Cited By ~ 9

Author(s):

Ghaida Hadaidi ◽

Maren Ziegler ◽

Amanda Shore-Maggio ◽

Thor Jensen ◽

Greta Aeby ◽

...

Keyword(s):

Microbial Community ◽

Red Sea ◽

Microbial Mats ◽

Heterotrophic Bacteria ◽

Coral Disease ◽

Differential Susceptibility ◽

Black Band Disease ◽

Southern Central ◽

Black Band

Black Band Disease (BBD) is a widely distributed and destructive coral disease that has been studied on a global scale, but baseline data on coral diseases is missing from many areas of the Arabian Seas. Here we report on the broad distribution and prevalence of BBD in the Red Sea in addition to documenting a bleaching-associated outbreak of BBD with subsequent microbial community characterization of BBD microbial mats at this reef site in the southern central Red Sea. Coral colonies with BBD were found at roughly a third of our 22 survey sites with an overall prevalence of 0.04%. Nine coral genera were infected including Astreopora, Coelastrea, Dipsastraea, Gardineroseris, Goniopora, Montipora, Pavona, Platygyra, and Psammocora. For a southern central Red Sea outbreak site, overall prevalence was 40 times higher than baseline (1.7%). Differential susceptibility to BBD was apparent among coral genera with Dipsastraea (prevalence 6.1%), having more diseased colonies than was expected based on its abundance within transects. Analysis of the microbial community associated with the BBD mat showed that it is dominated by a consortium of cyanobacteria and heterotrophic bacteria. We detected the three main indicators for BBD (filamentous cyanobacteria, sulfate-reducing bacteria (SRB), and sulfide-oxidizing bacteria (SOB)), with high similarity to BBD-associated microbes found worldwide. More specifically, the microbial consortium of BBD-diseased coral colonies in the Red Sea consisted of Oscillatoria sp. (cyanobacteria), Desulfovibrio sp. (SRB), and Arcobacter sp. (SOB). Given the similarity of associated bacteria worldwide, our data suggest that BBD represents a global coral disease with predictable etiology. Furthermore, we provide a baseline assessment of BBD disease prevalence in the Red Sea, a still understudied region.

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RNA-seq provides molecular insights into interaction modification in simplified microbial community

Access Microbiology ◽

10.1099/acmi.ac2020.po0801 ◽

2020 ◽

Vol 2 (7A) ◽

Author(s):

Frederik De Boever ◽

Philippe Potin ◽

David Green

Keyword(s):

Microbial Community ◽

Community Dynamics ◽

Heterotrophic Bacteria ◽

Context Dependency ◽

Emergent Properties ◽

Interspecies Interactions ◽

Transcriptional Responses ◽

Nutrient Analysis ◽

Primary Producer ◽

The Stability

A major challenge in microbial ecology is to understand the stability of interspecies interactions when progressing from pairs of interacting species to multispecies interaction networks. A lack of direct evidence, and a conceptual framework to explore how direct and indirect effects shape cellular responses in species-rich networks has hindered progress in our understanding of these combined effects. Here we aimed to investigate whether higher-order interactions shape community dynamics and transcriptional profiles of all interacting partners in a simplified microbial community that includes a primary producer (Nannochloropsis oceanica CCAP849/10) and two heterotrophic bacteria (Marinobacter sp. FDB33 and Alteromonas sp. FDB36). By combining co-cultivation assays, quantification of absolute abundances, nutrient analysis, and simultaneous RNA-sequencing, we reveal genome-wide transcriptional responses in all binary co-cultivation partners and show that the third partner can profoundly alter binary interactions at the phenotypic and transcription level. Our study demonstrates the context-dependency of binary interactions, whereby environmental conditions and the presence of specific organisms can affect the cellular physiology of the interacting partners and ultimately the stability of the community. Furthermore, our approach provides a powerful tool for probing the molecular basis of emergent properties in more complex systems.

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Optimizing biomethane production of mesophilic chicken manure and sheep manure digestion: Mono-digestion and co-digestion kinetic investigation, autofluorescence analysis and microbial community assessment

Journal of Environmental Management ◽

10.1016/j.jenvman.2019.02.050 ◽

2019 ◽

Vol 237 ◽

pp. 103-113 ◽

Cited By ~ 12

Author(s):

Liuying Song ◽

Dunjie Li ◽

Xiangyunong Cao ◽

Yu Tang ◽

Rutao Liu ◽

...

Keyword(s):

Microbial Community ◽

Chicken Manure ◽

Kinetic Investigation ◽

Community Assessment ◽

Sheep Manure ◽

Biomethane Production

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Performance and microbial community of the CANON process in a sequencing batch membrane bioreactor with elevated COD/N ratios

Water Science & Technology ◽

10.2166/wst.2020.089 ◽

2020 ◽

Vol 81 (1) ◽

pp. 138-147

Author(s):

Xiaoling Zhang ◽

Xincong Liu ◽

Meng Zhang

Keyword(s):

Organic Matter ◽

Microbial Community ◽

Nitrogen Removal ◽

Membrane Bioreactor ◽

Ammonia Oxidation ◽

Heterotrophic Bacteria ◽

Removal Rate ◽

Ammonia Oxidizing Bacteria ◽

Anaerobic Ammonia Oxidation ◽

Canon Process

Abstract In this study, the effects of elevated chemical oxygen demand/nitrogen (COD/N) ratios on nitrogen removal, production and composition of the extracellular polymer substances (EPS) and microbial community of a completely autotrophic nitrogen removal via nitrite (CANON) process were studied in a sequencing batch membrane bioreactor (SBMBR). The whole experiment was divided into two stages: the CANON stage (without organic matter in influent) and the simultaneous partial nitrification, anaerobic ammonia oxidation and denitrification (SNAD) stage (with organic matter in influent). When the inflow ammonia nitrogen was 420 mg/L and the COD/N ratio was no higher than 0.8, the addition of COD was helpful to the CANON process; the total nitrogen removal efficiency (TNE) was improved from approximately 65% to more than 75%, and the nitrogen removal rate (NRR) was improved from approximately 0.255 kgN/(m3·d) to approximately 0.278 kgN/(m3•d), while the TNE decreased to 60%, and the NRR decreased to 0.236 kgN/(m3•d) when the COD/N ratio was elevated to 1.0. For the EPS, the amounts of soluble EPS (SEPS) and loosely bound EPS (LB-EPS) were both higher in the CANON stage than in the SNAD stage, while the amount of tightly bound EPS (TB-EPS) in the SNAD stage was significantly higher due to the proliferation of heterotrophic bacteria. The metagenome sequencing technique was used to analyse the microbial community in the SBMBR. The results showed that the addition of COD altered the structure of the bacterial community in the SBMBR. The amounts of Candidatus ‘Anammoxoglobus’ of anaerobic ammonia oxidation bacteria (AAOB) and Nitrosomonas of ammonia oxidizing bacteria (AOB) both decreased significantly, and Nitrospira of nitrite oxidizing bacteria (NOB) was always in the reactor, although the amount changed slightly. A proliferation of denitrifiers related to the genera of Thauera, Dokdonella and Azospira was found in the SBMBR.

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