Study of microbial communities and environmental parameters of seawater collected from three Tunisian fishing harbors in Kerkennah Islands: Statistical analysis of the temporal and spatial dynamics.

Surface seawater, collected from three fishing harbors during different seasons of the years 2015, 2016 and 2017, were assessed for physico-chemical analyses. Results showed that seawater was mainly polluted by hydrocarbons and some heavy metals. Microbial communities' composition and abundance in the studied harbors were performed using molecular approaches.

Bacterial Consumption of T4 Phages.

The bacterial consumption of viruses not been reported on as of yet even though bacteria feed on almost anything. Viruses are widely distributed but have no acknowledged active biocontrol. Viral biomass undoubtedly reintegrates trophic cycles; however, the mechanisms of this phase still remain unknown.

Absolute quantitation of microbes using 16S rRNA gene metabarcoding: A rapid normalization of relative abundances by quantitative PCR targeting a 16S rRNA gene spike-in standard.

Metabarcoding of the 16S rRNA gene is commonly used to characterize microbial communities, by estimating the relative abundance of microbes. Here, we present a method to retrieve the concentrations of the 16S rRNA gene per gram of any environmental sample using a synthetic standard in minuscule amounts (100 ppm to 1% of the 16S rRNA sequences) that is added to the sample before DNA extraction and quantified by two quantitative polymerase chain reaction (qPCR) reactions. This allows normalizing by the initial microbial density, taking into account the DNA recovery yield.

Screening of Phytophagous and Xylophagous Insects Guts Microbiota Abilities to Degrade Lignocellulose in Bioreactor.

Microbial consortia producing specific enzymatic cocktails are present in the gut of phytophagous and xylophagous insects; they are known to be the most efficient ecosystems to degrade lignocellulose. Here, the ability of these consortia to degrade lignocellulosic biomass in anaerobic bioreactors was characterized in term of bioprocess performances, enzymatic activities and bacterial community structure. In a preliminary screening, guts of (beetle), (chafer), (cockroach), (locust), and (cricket) were inoculated in anaerobic batch reactors, in presence of grounded wheat straw at neutral pH.

Bacterial Shifts in Nutrient Solutions Flowing Through Biofilters Used in Tomato Soilless Culture.

In soilless culture, slow filtration is used to eliminate plant pathogenic microorganisms from nutrient solutions. The present study focused on the characterization and the potential functions of microbial communities colonizing the nutrient solutions recycled on slow filters during a whole cultivation season of 7 months in a tomato growing system. Bacterial microflora colonizing the solutions before and after they flew through the columns were studied.

Biodegradation of low and high molecular weight hydrocarbons in petroleum refinery wastewater by a thermophilic bacterial consortium.

Clean-up of contaminated wastewater remains to be a major challenge in petroleum refinery. Here, we describe the capacity of a bacterial consortium enriched from crude oil drilling site in Al-Khobar, Saudi Arabia, to utilize polycyclic aromatic hydrocarbons (PAHs) as sole carbon source at 60°C. The consortium reduced low molecular weight (LMW; naphthalene, phenanthrene, fluorene and anthracene) and high molecular weight (HMW; pyrene, benzo(e)pyrene and benzo(k)fluoranthene) PAH loads of up to 1.

Halotolerant bioanodes: The applied potential modulates the electrochemical characteristics, the biofilm structure and the ratio of the two dominant genera.

The development of economically-efficient microbial electrochemical technologies remains hindered by the low ionic conductivity of the culture media used as the electrolyte. To overcome this drawback, halotolerant bioanodes were designed with salt marsh sediment used as the inoculum in electrolytes containing NaCl at 30 or 45g/L (ionic conductivity 7.0 or 10.

Biodegradation of fluoranthene by a newly isolated strain of Bacillus stratosphericus from Mediterranean seawater of the Sfax fishing harbour, Tunisia.

A physico-chemical characterization of seawater taken from the fishing harbour of Sfax, Tunisia, revealed a contamination by organic and inorganic micropollutants. An aerobic marine halotolerant Bacillus stratosphericus strain FLU5 was isolated after enrichment on fluoranthene, a persistent and toxic polycyclic aromatic hydrocarbon (PAH). GC-MS analyses showed that strain FLU5 was capable of degrading almost 45 % of fluoranthene (100 mg l(-1)), without yeast extract added, after 30 days of incubation at 30 g l(-1) NaCl and 37 °C.

Vertebrate bacterial gut diversity: size also matters.

Background: One of the central issues in microbial ecology is to understand the parameters that drive diversity. Among these parameters, size has often been considered to be the main driver in many different ecosystems. Surprisingly, the influence of size on gut microbial diversity has not yet been investigated, and so far in studies reported in the literature only the influences of age, diet, phylogeny and digestive tract structures have been considered.

Microbial community structure associated with the high loading anaerobic codigestion of olive mill and abattoir wastewaters.

The effect of increasing the organic loading rates (OLRs) on the performance of the anaerobic codigestion of olive mill (OMW) and abattoir wastewaters (AW) was investigated under mesophilic and thermophilic conditions. The structure of the microbial community was also monitored. Increasing OLR to 9g of chemical oxygen demand (COD) L(-1)d(-1) affected significantly the biogas yield and microbial diversity at 35°C.

Asymmetrical response of anaerobic digestion microbiota to temperature changes.

In natural settings, anaerobic digestion can take place in a wide temperature range, but industrial digesters are usually operated under either mesophilic (~35 °C) or thermophilic (~55 °C) conditions. The ability of anaerobic digestion microbiota to switch from one operating temperature to the other remains poorly documented. We therefore studied the effect of sudden temperature changes (35 °C/55 °C) in lab-scale bioreactors degrading C-labelled cellulose.

Shotgun metaproteomic profiling of biomimetic anaerobic digestion processes treating sewage sludge.

Two parallel anaerobic digestion lines were designed to match a "bovid-like" digestive structure. Each of the lines consisted of two continuous stirred tank reactors placed in series and separated by an acidic treatment step. The first line was inoculated with industrial inocula whereas the second was seeded with cow digestive tract contents.

Seasonal Variation on Microbial Community and Methane Production during Anaerobic Digestion of Cattle Manure in Brazil.

Anaerobic digestion is an alternative method for the treatment of animal manure and wastewater. The anaerobic bioconversion of biomass requires a multi-step biological process, including microorganisms with distinct roles. The diversity and composition of microbial structure in pilot-scale anaerobic digestion operating at ambient temperature in Brazil were studied.

Microbial characterization of anode-respiring bacteria within biofilms developed from cultures previously enriched in dissimilatory metal-reducing bacteria.

This work evaluated the use of a culture enriched in DMRB as a strategy to enrich ARB on anodes. DMRB were enriched with Fe(III) as final electron acceptor and then transferred to a potentiostatically-controlled system with an anode as sole final electron acceptor. Three successive iron-enrichment cultures were carried out.

Invasibility of resident biofilms by allochthonous communities in bioreactors.

Invasion of non-native species can drastically affect the community composition and diversity of engineered and natural ecosystems, biofilms included. In this study, a molecular community fingerprinting method was used to monitor the putative establishment and colonization of allochthonous consortia in resident multi-species biofilms. To do this, biofilms inoculated with tap water or activated sludge were grown for 10 days in bubble column reactors W1 and W2, and S, respectively, before being exposed to non-native microbial consortia.

Specific and efficient electrochemical selection of Geoalkalibacter subterraneus and Desulfuromonas acetoxidans in high current-producing biofilms.

Two different saline sediments were used to inoculate potentiostatically controlled reactors (a type of microbial bioelectrochemical system, BES) operated in saline conditions (35 gNaCl l(-1)). Reactors were fed with acetate or a mixture of acetate and butyrate at two pH values: 7.0 or 5.

Needles of Pinus halepensis as biomonitors of bioaerosol emissions.

We propose using the surface of pine trees needles to biomonitor the bioaerosol emissions at a composting plant. Measurements were based on 16S rRNA gene copy numbers of Saccharopolyspora rectivirgula, a bioindicator of composting plant emissions. A sampling plan was established based on 29 samples around the emission source.

Only Simpson diversity can be estimated accurately from microbial community fingerprints.

Lalande et al. (Microb. Ecol.

'Core species' in three sources of indoor air belonging to the human micro-environment to the exclusion of outdoor air.

Although we spend the majority of our lives indoors, the airborne microbial content of enclosed spaces still remains inadequately described. The objective of this study was to characterize the bacterial diversity of indoor air in three different enclosed spaces with three levels of occupancy, and, in particular, to highlight the 'core' species, the opportunistic pathogens and their origins. Our findings provide an overall description of bacterial diversity in these indoor environments.

Disturbance frequency determines morphology and community development in multi-species biofilm at the landscape scale.

Many natural and engineered biofilm systems periodically face disturbances. Here we present how the recovery time of a biofilm between disturbances (expressed as disturbance frequency) shapes the development of morphology and community structure in a multi-species biofilm at the landscape scale. It was hypothesized that a high disturbance frequency favors the development of a stable adapted biofilm system while a low disturbance frequency promotes a dynamic biofilm response.

Performance study of biofilter developed to treat H2S from wastewater odour.

Biofiltration is an efficient biotechnological process used for waste gas abatement in various industrial processes. It offers low operating and capital costs and produces minimal secondary waste streams. The objective of this study was to evaluate the performance of a pilot scale biofilter in terms of pollutants' removal efficiencies and the bacterial dynamics under different inlet concentrations of H2S.

Impact of microbial diversity depletion on xenobiotic degradation by sewage-activated sludge.

Microbial diversity is generally considered as having no effect on the major processes of the ecosystem such as respiration or nutrient assimilation. However, information about the impact of diversity on minor functions such as xenobiotic degradation is scant. We studied the role of diversity on the capacity of an activated-sludge microbial community to eliminate phenanthrene, a polycyclic aromatic hydrocarbon.

Microbial monitoring by molecular tools of an upflow anaerobic filter treating abattoir wastewaters.

The performance of anaerobic digestion of abattoir wastewaters (AW) in an upflow anaerobic filter (UAF) was investigated under mesophilic (37°C) and thermophilic (55°C) conditions. The effects of increasing temperature on the performance of the UAF and on the dynamics of the microbial community of the anaerobic sludge were studied. The results showed that chemical oxygen demand (COD) removal efficiency of 90% was achieved for organic loading rates (OLRs) up to 4.