Fungal treatment of agricultural washing wastewater: Comparison between two operational strategies.

Agricultural washing wastewater (AWW) is an important source of pesticides that, given its intrinsic characteristics, has a high potential to be treated by fungal bioremediation using white rot fungi. In the present study, two AWW treatment strategies were compared: a fluidized-bed reactor (FBR) with T. versicolor pellets and a rotating drum bioreactor (RDB) with T.

Fungal bioremediation of agricultural wastewater in a long-term treatment: biomass stabilization by immobilization strategy.

Fungal bioremediation emerges as an effective technology for pesticide treatment, but its successful implementation depends on overcoming the problem of microbial contamination. In this regard, fungal immobilization on wood seems to be a promising strategy, but there are two main drawbacks: the predominant removal of pesticides by sorption and fungal detachment. In this study, agricultural wastewater with pesticides was treated by Trametes versicolor immobilized on wood chips in a rotary drum bioreactor (RDB) for 225 days, achieving fungal consolidation and high pesticide biodegradation through two main improvements: the use of a more favorable substrate and the modification of operating conditions.

Long-term continuous treatment of non-sterile real hospital wastewater by .

Background: Hospital wastewater is commonly polluted with high loads of pharmaceutically active compounds, which pass through wastewater treatment plants (WWTPs) and end up in water bodies, posing ecological and health risks. White-rot fungal treatments can cope with the elimination of a wide variety of micropollutants while remaining ecologically and economically attractive. Unfortunately, bacterial contamination has impeded so far a successful implementation of fungal treatment for real applications.

Are dominant microbial sub-surface communities affected by water quality and soil characteristics?

Subsurface microorganisms must deal with quite extreme environmental conditions. The lack of light, oxygen, and potentially nutrients are the main environmental stresses faced by subsurface microbial communities. Likewise, environmental disruptions providing an unbalanced positive input of nutrients force microorganisms to adapt to varying conditions, visible in the changes in microbial community diversity.

Effect of cultivation conditions on β-estradiol removal in laboratory and pilot-plant photobioreactors by an algal-bacterial consortium treating urban wastewater.

The use of microalgal consortia for urban wastewater treatment is an increasing trend, as it allows simultaneous nutrient removal and biomass production. Emerging contaminants proposed for the list of priority substances such as the hormone 17β-estradiol are commonly found in urban wastewater, and their removal using algal monocultures has been accomplished. Due to the inherent potential of algae-based systems, this study aimed to assess the capability of native photobioreactor biomass to remove 17β-estradiol under indoor and outdoor conditions.

A comparison between biostimulation and bioaugmentation in a solid treatment of anaerobic sludge: Drug content and microbial evaluation.

Emerging pollutants can reach the environment through the sludge of Wastewater Treatment Plants. In this work, the use of Trametes versicolor in biopiles at lab-scale was studied, evaluating its capacity to remove the most hydrophobic Pharmaceuticals and assessing the evolution of the biopiles microbial communities. The total removal of drugs at real concentrations from sewage sludge was assessed for non-inoculated and fungal inoculated biopiles, testing if the re-inoculation of the biopiles after 22 days of treatment would improve the removal yields.

Pharmaceuticals removal and microbial community assessment in a continuous fungal treatment of non-sterile real hospital wastewater after a coagulation-flocculation pretreatment.

Hospital wastewaters are a main source of pharmaceutical active compounds, which are usually highly recalcitrant and can accumulate in surface and groundwater bodies. Fungal treatments can remove these contaminants prior to discharge, but real wastewater poses a problem to fungal survival due to bacterial competition. This study successfully treated real non-spiked, non-sterile wastewater in a continuous fungal fluidized bed bioreactor coupled to a coagulation-flocculation pretreatment for 56 days.

Molecular and carbon isotopic characterization of an anaerobic stable enrichment culture containing Dehalobacterium sp. during dichloromethane fermentation.

Unlabelled: Biodegradation of dichloromethane (DCM) under reducing conditions is of major concern due to its widespread detection in contaminated groundwaters. Here, we report an anaerobic enrichment culture derived from a membrane bioreactor operating in an industrial wastewater treatment plant, capable of fermenting DCM and the brominated analogue dibromomethane (DBM). Comparative analysis of bacterial 16S rDNA-DGGE profiles from fresh liquid medium inoculated with single colonies picked from serial dilution-to-extinction agar vials showed that cultures degrading DCM contained a predominant band belonging to Dehalobacterium, however this band was absent in cultures unable to degrade DCM.

Characterization of Soil Suppressiveness to Root-Knot Nematodes in Organic Horticulture in Plastic Greenhouse.

The fluctuation of Meloidogyne population density and the percentage of fungal egg parasitism were determined from July 2011 to July 2013 in two commercial organic vegetable production sites (M10.23 and M10.55) in plastic greenhouses, located in northeastern Spain, in order to know the level of soil suppressiveness.

Stable Carbon Isotope Fractionation During 1,2-Dichloropropane-to-Propene Transformation by an Enrichment Culture Containing Dehalogenimonas Strains and a dcpA Gene.

A stable enrichment culture derived from Besòs river estuary sediments stoichiometrically dechlorinated 1,2-dichloropropane (1,2-DCP) to propene. Sequential transfers in defined anaerobic medium with the inhibitor bromoethanesulfonate produced a sediment-free culture dechlorinating 1,2-DCP in the absence of methanogenesis. Application of previously published genus-specific primers targeting 16S rRNA gene sequences revealed the presence of a Dehalogenimonas strain, and no amplification was obtained with Dehalococcoides-specific primers.

Organic amendments to avocado crops induce suppressiveness and influence the composition and activity of soil microbial communities.

One of the main avocado diseases in southern Spain is white root rot caused by the fungus Rosellinia necatrix Prill. The use of organic soil amendments to enhance the suppressiveness of natural soil is an inviting approach that has successfully controlled other soilborne pathogens. This study tested the suppressive capacity of different organic amendments against R.

Diversity of the bacterial community in the surface soil of a pear orchard based on 16S rRNA gene analysis.

A cultivation-independent approach based on polymerase chain reaction (PCR)-amplified partial small subunit rRNA genes was used to characterize bacterial populations in the surface soil of a commercial pear orchard consisting of different pear cultivars during two consecutive growing seasons. Pyrus communis L. cvs Blanquilla, Conference, and Williams are among the most widely cultivated cultivars in Europe and account for the majority of pear production in Northeastern Spain.

Microcosm experiments of oil degradation by microbial mats. II. The changes in microbial species.

The influence of microbial mats on the degradation of two crude oils (Casablanca and Maya) and the effect of oil pollution on the mat structure were assessed using model ecosystems, prepared under laboratory conditions subject to tidal movements, from pristine Ebro Delta microbial-mat ecosystems. Both selected oils are examples of those currently used for commercial purposes. Casablanca crude oil is aliphatic with a low viscosity; Maya represents a sulphur-rich heavy crude oil that is predominantly aromatic.

Spatial heterogeneity of bacterial populations in monomictic Lake Estanya (Huesca, Spain).

Bacterial population changes were investigated in the monomictic Lake Estanya by combining microscopic analysis and two molecular methods involving the amplification of 16S rDNA genes using primers for the domain Bacteria and subsequent restriction fragment length polymorphism (PCR-RFLP) and denaturing gradient gel electrophoresis (PCR-DGGE). Both approaches revealed the vertical distribution of predominant microbial morphotypes and phylotypes in both holomictic and stratified periods, respectively, and showed that variations in structure and composition of bacterial populations are occurring in this lake as a function of depth and time. Through principal component analysis (PCA), these shifts could be related to different physicochemical parameters with temperature, oxygen concentration, and the incident light being of paramount importance as structuring variables.

Seasonal microbial ribotype shifts in the sulfurous karstic lakes Cisó and Vilar, in northeastern Spain.

Spatio-temporal changes in two sulfurous lakes from the karstic area of Banyoles (Girona, Spain), holomictic lake Cisó and meromictic lake Vilar, were studied over one year. Samples were collected at different depths from the two lakes on the same days, during each of the four seasons, and several physico-chemical variables (temperature, light, pH, conductivity, sulfide, oxygen concentration, pigment concentrations, etc.) were measured.

Morphological and ultrastructural characterization of an unusual purple sulfur bacterium from a marine microbial-mat community.

An unusual purple sulfur bacterium present in the pink layer of the Ebro Delta microbial mats has been identified through the study of its ultrastructural features. As pure cultures of this bacterium have not been obtained, due to its inability to grow in axenic conditions, only enrichment cultures where it reached at least 90% of total biomass have been considered. In enrichment cultures, the cells are rods that are 5.

Diversity of anoxygenic phototrophic sulfur bacteria in the microbial mats of the Ebro Delta: a combined morphological and molecular approach.

The diversity of purple and green sulfur bacteria in the multilayered sediments of the Ebro Delta was investigated. Specific oligonucleotide primers for these groups were used for the selective amplification of 16S rRNA gene sequences. Subsequently, amplification products were separated by denaturing gradient gel electrophoresis and sequenced, which yielded a total of 32 sequences.

Distribution of phototrophic populations and primary production in a microbial mat from the Ebro Delta, Spain.

Microbial mats arising in the sand flats of the Ebro Delta (Tarragona, Spain) were investigated during the summer season, when the community was highly developed. These mats are composed of three pigmented layers of phototrophic organisms, an upper brown layer mainly composed of Lyngbya aestuarii and diatoms, an intermediate green layer of the cyanobacterium Microcoleus chthonoplastes, and an underlying pink layer of a so-far unidentified purple sulfur bacterium. In the photic zone, oxygenic phototrophs constitute about 58% of total photosynthetic biomass, measured as biovolume, and anoxygenic phototrophs represent 42%.

Factors affecting interpretation of restriction fragment length polymorphism (RFLP) patterns from PCR-amplified bacterial 16S rRNA genes: operon number and primer mismatching.

PCR methods have been shown to be biased by several factors. In the present study, we have developed a theoretic and practical approximation to elucidate how the presence of mismatches at the primers annealing regions and the different number of rDNA operons per cell can influence PCR and subsequent restriction fragment length polymorphism (RFLP) analyses from bacterial populations. We have performed RFLP analyses of 16S rRNA genes amplified by PCR from mixed bacterial cultures showing different primer identities and number of rDNA operons.

The biomass dynamics of cyanobacteria in an annual cycle determined by confocal laser scanning microscopy.

We recently published a method for estimating cyanobacteria biomass in delta microbial mats from the Ebro river using confocal laser scanning microscopy (CLSM). The present paper uses this method for identifying different groups of cyanobacteria and for determining their biomass dynamics. Microcoleus chthonoplastes and the Lyngbya-Oscillatoria were the most important contributors to the cyanobacterial biomass throughout the study.

Seasonal population changes in the restriction fragment length polymorphism (RFLP) patterns from PCR-amplified 16S rRNA genes of predominant ribotypes in microbial mat samples from the Ebro Delta (Spain).

The stratified benthic microbial communities, which developed as a consequence of the physico-chemical gradients and the physiology of the inhabiting microorganisms, from Ebro Delta microbial mats were analyzed. 16S rRNA eubacterial and archaeal genes were amplified by polymerase chain reaction (PCR). PCR products were separately digested with three different restriction enzymes (AluI, HinfI, and RsaI) and later separated by horizontal electrophoresis to determine whether changes of predominant ribotypes are occurring over a period of a year.

Confocal laser scanning microscopy as a tool to determine cyanobacteria biomass in microbial mats.

We have developed a method based on confocal laser scanning microscopy for detection and quantification of cyanobacteria from the Ebro Delta microbial mats. Cyanobacteria play a major role as primary producers in microbial mats; it is difficult, however, to apply classical methods to estimate their biomass because they establish strong interactions with detritic particles. The protocol described here allows the localization of individual cells or filaments with micrometre precision without the need to either manipulate or stain the samples.

Molecular taxonomy of the genus Chlorobium.

This review summarizes molecular studies on the taxonomy of the genus Chlorobium. Furthermore, we try to introduce a comprehensive view of how joining traditional phenotypic-based taxonomy with the current molecular approaches leads to a more natural classification. Moreover, we introduce the current insights that molecular techniques have brought to the detection and identification of nonisolated Chlorobium strains in their environments.

Bacterial symbioses. Predation and mutually beneficial associations.

The endosymbiotic theory, which has proved to explain the origin of mitochondria and chloroplasts, also posits the origin of nucleus and other cellular organelles that could have derived from ancient relationships among bacteria. It seems that predation might have been a prerequisite to the establishment of symbiosis as a source of evolutionary novelty. This review describes current different examples of bacteria able not only to attack and degrade other bacteria, but also to establish stable symbiotic relationships with different eukaryotic organisms.

A mathematical model to determine the optimal number of fragments for comparison of bacterial chromosomic macrorestriction patterns.

To our knowledge, although comparison of chromosomic macrorestriction patterns has become one of the most feasible molecular tools of the current microbial taxonomy, a mathematical approach to optimize the choice of a restriction enzyme among the endonucleases tested for such comparison has not been previously described. The coincidence of restriction patterns for two tested bacterial strains with this chosen endonuclease will ensure a high genetic relatedness between them. We report a mathematical model to determine the probability of hazardously obtaining a particular chromosomic macrorestriction pattern by PFGE and to calculate the optimal number of fragments for its comparison.