Search

As a result of mining activities, waste of different types is generated. One example is mine tailings that contain potentially toxic elements such as heavy metals that negatively impact the environment and human health. Hence, developing treatments to guarantee its efficient elimination from the environment is necessary. Among these treatments, phytoremediation takes advantage of the potential of different plant species, to remove heavy metals from polluted sites. Gliricidia sepium is a tree that grows up to 15 m high and distributed from southern Mexico to Central America. This study evaluates the heavy metal bioaccumulation capacity in roots and leaves, and the effect of such bioaccumulation on fifteen macro- and one micro-morphological characters of G. sepium growing during 360 days in control, and in mine tailing substrates. G. sepium individuals growing on the exposed substrate registered the following average heavy metal bioaccumulation pattern in the roots: Fe Pb Zn Cu, while in the leaf tissue, the bioaccumulation pattern was Cu Fe Pb Zn. Macro- and micro-morphological characters evaluated in G. sepium decreased in plants exposed to metals. The translocation factor showed that Cu and Pb registered average values greater than 1. In conclusion, G. sepium is a species with potential for the phytoremediation of soils contaminated with Fe, Cu, and Pb, and for phytostabilizing soils polluted with Fe, Pb, Zn, and Cu, along with its ability to establish itself and turn into an abundant plant species in polluted sites, its capacity to bioaccumulate heavy metals in roots and leaves, and its high rate of HM translocation.

The purpose of this work was to produce iron nanoparticles (Fe-NP) by microbial pathway from anaerobic bacteria grown in anaerobic fluidized bed reactors (AnFBRs) that constitute a new stage of a waste-based biorefinery. Bioparticles from biological fluidized bed reactors from a biorefinery of organic fraction of municipal solid wastes (that produces hydrolysates rich in reducing sugars) were nanodecorated (embedded nanobioparticle or nanodecorated bioparticle, ENBP) by biological reduction of iron salts. Factors “origin of bioparticles” (either from hydrogenogenic or methanogenic fluidized bed reactor) and “type of iron precursor salt” (iron chloride or iron citrate) were explored. SEM and high-resolution transmission electron microscopy (HRTEM) showed amorphous distribution of nanoparticles (NP) on the bioparticles surface, although small structures that are nanoparticle-like could be seen in the SEM micrographs. Some agglomeration of NPs was confirmed by DLS. Average NP size was lower in general for NP in ENBP-M than ENBP-H according to HRTEM. The factors did not have a significant influence on the specific surface area of NPs, which was high and in the range 490 to 650 m2 g−1. Analysis by EDS displayed consistent iron concentration 60–65% iron in nanoparticles present in ENBP-M (bioparticles previously grown in methanogenic bioreactor), whereas the iron concentration in NPs present in ENBP-H (bioparticles previously grown in hydrogenogenic bioreactor) was more variable in a range from 8.5 to 62%, depending on the iron salt. X-ray diffraction patterns showed the typical peaks for magnetite at 35° (3 1 1), 43° (4 0 0), and 62° (4 0 0); moreover, siderite diffraction pattern was found at 26° (0 1 2), 38° (1 1 0), and 42° (1 1 3). Results of infrared analysis of ENBP in our work were congruent with presence of magnetite and occasionally siderite determined by XRD analysis as well as presence of both Fe+2 and F+3 (and selected satellite signal peaks) observed by XPS. Our results on the ENBPs hold promise for water treatment, since iron NPs are commonly used in wastewater technologies that treat a wide variety of pollutants. Finally, the biological production of ENBP coupled to a biorefinery could become an environmentally friendly platform for nanomaterial biosynthesis as well as an additional source of revenues for a waste-based biorefinery.

Methanobacterium paludis is a hydrogenotrophic archaea first described in 2014 and isolated from a peatland area. So far, there is only one sequenced genome of this taxon. Here, we report the draft genome sequence of M. paludis IBT-C12, a metagenome-assembled genome (MAG) from sediments in the Apatlaco River, Mexico.

This work aimed to synthesize and characterize nanoscale zero-valent iron (nZVI), supported on diatomaceous earth (DE) at two different molar concentrations, 3 and 4 M (nZVI-DE-1 nZVI-DE-2), to test the decolorization treatment of acid blue dye (AB) and perform a toxicological test using zebrafish. The synthesis of the nanoparticles was obtained using the chemical reduction method. The material was fully characterized by X-ray diffraction, scanning electron microscopy (SEM), energy-dispersive X-ray (EDX), and transmission electron microscopy and specific surface area (BET). The results showed spherical forms in clusters between 20 and 40 nm of zero-valent iron supported on diatomaceous earth. The removal of 1 g/L of AB from water treated with nZVI-DE-1 and nZVI-DE-2 reached the decolorization of 90% and 98% of all dye. By contrast, controls such as nZVI and DE-1 and DE-2 removed 40%, 37%, and 24% of the dye. Toxicological analysis using zebrafish showed that AB causes a severe defect in development, and embryos die after exposure. However, the water samples treated with nZVI-DE-1 and nZVI-DE-2 are not harmful to the zebrafish embryos during the first 24 h. However, all embryos exposed to the new material for more than 48 hpf had cardiac edema, smaller eyes, and curved and smaller bodies with less pigmentation.

Microbial biodiversity is represented by a variety of genomic landscapes adapted to dissimilar environments on Earth. These genomic landscapes contain functional signatures connected with the community phenotypes. Here, we assess the genomic microbial diversity landscape at a high-resolution level of a polluted river–associated microbiome (Morelos, Mexico), cultured in a medium enriched with anthraquinone Deep Blue 35 dye. We explore the resultant textile dye microbiome to infer links between predicted biodegradative functions, and metagenomic and metabolic potential, especially using the information obtained from individual reconstructed genomes. By using Hi-C proximity-ligation deconvolution method, we deconvoluted 97 genome composites (80% potentially novel species). The main taxonomic determinants were Methanobacterium, Clostridium, and Cupriavidus genera constituting 50, 22, and 11% of the total community profile. Also, we observed a rare biosphere of novel taxa without clear taxonomic standing. Removal of 50% chemical oxygen demand with 23% decolorization was observed after 30 days of dye enrichment. Genes related to catalase-peroxidase, polyphenol oxidase, and laccase enzymes were predicted as associated with textile dye biodegradation phenotype under our study conditions, highlighting the potential of metagenome-wide analysis to predict biodegradative determinants. This study prompts high-resolution screening of individual genomes within textile dye river sediment microbiomes or complex communities under environmental pressures.

Maize forms the basis of Mexican food. As a result, approximately six million tons of corncob are produced each year, which represents an environmental issue, as well as a potential feedstock for biogas production. This research aimed to analyze the taxonomic and functional shift in the microbiome of the fermenters using a whole metagenome shotgun approach. Two strategies were used to understand the microbial community at the beginning and the end of anaerobic digestion: (i) phylogenetic analysis to infer the presence and coverage of clade-specific markers to assign taxonomy and (ii) the recovery of the individual genomes from the samples using the binning of the assembled scaffolds. The results showed that anaerobic digestion brought some noticeable changes and the main microbial community was composed of Corynebacterium variable, Desulfovibrio desulfuricans, Vibrio furnissii, Shewanella spp., Actinoplanes spp., Pseudoxanthomonas spp., Saccharomonospora azurea, Agromyces spp., Serinicoccus spp., Cellulomonas spp., Pseudonocardia spp., Rhodococcus rhodochrous, Sphingobacterium spp. Methanosarcina mazei, Methanoculleus hydrogenitrophicus, Methanosphaerula spp., Methanoregula spp., Methanosaeta spp. and Methanospirillum spp. This study provides evidence of the drastic change in the microbial community structure in a short time and the functional strategy that the most representative microorganisms of the consortia used to carry out the process.

Microbial biodiversity is represented by genomic landscapes populating dissimilar environments on earth. These genomic landscapes usually contain microbial functional signatures connected with the community phenotypes. Here we assess the genomic microbiodiversity landscape of a river associated microbiome enriched with 200 mg.mL−1 of anthraquinone Deep-Blue 35 (™); we subjected to nutritional selection a composite sample from four different sites from a local river basin (Morelos, Mexico). This paper explores the resultant textile-dye microbiome, and infer links between predicted biodegradative functions and the individual genome fractions. By using a proximity-ligation deconvolution method, we deconvoluted 97 genome composites, with 80% of this been potentially novel species associated with the textile-dye environment. The main determinants of taxonomic composition were the genera Methanobacterium, Clostridium, and Cupriavidus constituting 50, 22, and 11 % of the total population profile respectively; also we observe an extended distribution of novel taxa without clear taxonomic standing. Removal of 50% chemical oxygen demand (COD) with 23% decolorization was observed after 30 days after dye enrichment. By metagenome wide analysis we postulate that sequence elements related to catalase-peroxidase, polyphenol oxidase, and laccase enzymes may be causally associated with the textile-dye degradation phenotype under our study conditions. This study prompts rapid genomic screening in order to select statistically represented functional features, reducing costs, and experimental efforts. As well as predicting phenotypes within complex communities under environmental pressures.

Objectives In order to characterize a river-associated, enriched microbiome capable of degrading an anthraquinone dye from the oil blue family, as well as assessing its functional potential, we performed a taxa-specific metagenomic deconvolution analysis based on contact probability maps at the chromosomal level. This study will allow associating the genomic content of “Candidatus Afipia apatlaquensis” strain IBT-C3 with its phenotypic potential in the context of bioremediation of textile dyes. We anticipate that this resource will be very useful in comparative genomic clinical studies, contributing to understanding the genomic basis of Afipia pathogenicity. Data description Here, we report the first draft genome sequence of “Candidatus Afipia apatlaquensis” sp. nov., strain IBT-C3, obtained by deconvolution of a textile-dye degrader microbiome in Mexico. The genome composite was deconvoluted using a Hi-C proximity ligation method. Whole-genome-based comparisons and phylogenomics reconstruction indicate that strain IBT-C3 represents a new species of the genus Afipia. The assembly completeness was 92.5% with 5,604,749 bp in length and 60.72% G+C content. The genome complement of IBT-C3 suggests a functional potential for decolorization of textile dyes, contrasting with previous reports of Afipia genus focused on its pathogenic potential.

This paper describes an organosolv pretreatment of corncob waste to improve its anaerobic digestion for biogas production. Through a thermochemical process based on the use of ethanol and acetic acid, it was possible to separate the fractions of lignin, considered to be a natural inhibitor of anaerobic digestion processes. In addition, with this organosolv pretreatment, the available sugars in the carbohydrates present as monosaccharides, or simple sugars, were depolymerised, facilitating the digestion process. The obtained results include the chemical characterisation of the corncob, the hydrolysate, and the mixture with cow manure, finding that these substrates have potential to be used in anaerobic digestion. The total reducing sugars consumed were 96.8%, and total sugars were 85.75%. It was clearly observed that with the use of pretreatment with organosolv, the production of biogas was superior, because 484 NmL/gVS was obtained compared to the other reported treatments. It was also observed that adding the hydrolysate organosolv increased the production because the values of the control without hydrolysate were 120 NmL/gVS in the bottle experiment. When the experiment was scaled to the 5L reactor, the total volumes of biogas that were accumulated in 15 days of production were 5050 NmL/gVS and 1212 NmL/gVS with and without hydrolysate, respectively. This indicates that the organosolv pretreatment of corncob waste is effective in improving biogas production.

ISEBE : International Symposium on Environmental Biotechnology and Engineering, Mexico, MEX, -; This is the editorial of the special issue published in Environmental Science and Pollution Research with articles presented at the occasion of the 6th edition of the International Symposium on Environmental Biotechnology and Engineering (6ISEBE) after peer review selection

The objective of this work was to assess the impact of perchloroethylene (PCE) and coupled zero valent iron (ZVI) filters on the transient performance of fluidized bed bioreactors (FBBRs) operated in simultaneous electron acceptors modes. Four lab scale, FBBRs were implemented. Two FBBRs were operated as simultaneous methanogenic-denitrifying (MD) units, whereas the other two were operated in partially-aerated methanogenic (PAM) mode. In the first period all FBBRs received a synthetic wastewater with 1 g COD-methanol/L. In a second period, all the FBBRs received the synthetic wastewater plus 80 mg PCE/L. At the start of period 2, one MD and one PAM FBBRs were coupled to side sand-ZVI filters. All bioreactors anchored microbial consortia unacclimated to PCE. In this work, bioreactor performance in the full period 1 and the first 15 days of period 2 (transient state) is reported and discussed. The chemical oxygen demand and the nitrate removal efficiency of the FBBRs did not decrease between period 1 and period 2, i.e., upon PCE addition, particularly for MD bioreactors. On the contrary, specific oxygen uptake rate of all FBBRs in period 2 decreased by ca. 80 to 96 % or more compared to period 1. In period 2, PCE removals and dehalogenation efficiency were in the range of 81 to 94 % and 73 to 90 %, respectively. The highest values corresponded to PAM bioreactors, particularly for that equipped with ZVI filter. Slight positive effects of ZVI filter on PCE removal and the dehalogenation efficiencies were observed in the PAM ZVI bioreactor configuration. It is concluded that the simultaneous electron acceptor type (PAM vs. MD) had a significant effect on the bioreactor performance, whereas the coupling to ZVI filters only had a slight positive effect on the bioreactor performance in the PAM-ZVI bioreactor.

The aim of this work was to synthesize and characterize nanoscale zero-valent iron (NZVI) supported on diatomaceous earth (DE) at two different molar concentration 3 M and 4M (nZVI-DE-1 nZVI-DE-2), to test the decolorization treatment of acid blue dye (AB) and perform a toxicological test using zebrafish. The synthesis of the nanoparticles was obtained using the chemical reduction method and the material was characterized by X-ray diffraction, Scanning Electron Microscopy (SEM), Energy-Dispersive X-Ray (EDX), and transmission electron microscopy and Specific Surface Area (BET). The results showed spherical forms in clusters between 20 to 40 nm of zero valent iron supported on diatomaceous earth. The removal of 1 g/l of AB from water treated with NZVI-DE-1 and NZVI-DE-2 reached the decolorization of 90% and 98% of all dye. While controls like NZVI and DE-1 and DE-2 achieved the removal of 40, 37 and 24 % of the dye. Toxicological analysis using zebrafish showed that AB causes a severe defect in development and embryos die after exposure. However, the water samples treated with NZVI-DE-1 and NZVI-DE-2 are not harmful for the zebrafish embryos during the first 24 hours. We conclude that the use of NZVI-DE-1 and NZVI-DE-2 is a promising treatment for dye pollution.

The objective of this study is to understand the functional potential of the microbial community related to bioremediation activity and its relationship with the pollution of each site to enhance the future design of more accurate bioremediation processes. Water samples were collected at four sampling sites along the Apatlaco River (S1-S4), and a whole metagenome shotgun sequencing was performed to know and understand the microbial community involved in bioremediation. Additionally, HMMER was used for searching sequence homologs related to PET and polystyrene biodegradation and metal transformation in Apatlaco River metagenomes. The Apatlaco River is characterized by the presence of a broad spectrum of microorganisms with the metabolic potential to carry out bioremediation activities. Every site along the Apatlaco River has a particular community to perform bioremediation activities. The first site S1 has Thiomonas, Polaromonas, Pedobacter, and Myroides, S2 has Pedobacter, Myroides, Pseudomonas and Acinetobacter, S3, Thiomonas, Myroides, Pseudomonas, Acinetobacter and Aeromonas; S4, Thiomonas, Myroides and Pseudomonas, Thauera.Furthermore, every site is rich in specific enzymes such as S1 has dioxygenase and dehydrogenase, which can degrade Catechol, Biphenyl, Naphthalene, and Phthalate. While, S2 and S3 are rich in dioxygenase and decarboxylating dehydrogenases to degrade Toluene, Fluorobenzoate, Xylene, Phenylpropanoate, and Phenol. S3 also has monooxygenases which degrade Benzene, and all the earlier mentioned enzymes were also found at S4.

The increasing demand for clean water resources for human consumption, is raising concerning about the sustainable worldwide provisioning. In Mexico, rivers near to high-density urbanizations are subject to irrational exploitation where polluted water is a risk for human health. Therefore, the aims of this study are to analyze water quality parameters and bacterial community dynamics to understand the relation between them, in the Apatlaco river, which presents a clear environmental perturbance. Parameters such as total coliforms, chemical oxygen demand, harness, ammonium, nitrite, nitrate, total Kjeldahl nitrogen, dissolved oxygen, total phosphorus, total dissolved solids, and temperature were analyzed in 17 sampling points along the river. The high pollution level was registered in the sampling point 10 with 480 mg/L chemical oxygen demand, 7 mg/L nitrite, 34 mg/L nitrate, 2 mg/L dissolved oxygen, and 299 mg/L of total dissolved solids. From these sites, we selected four samples for DNA extraction and performed a metagenomic analysis using a whole metagenome shotgun approach, to compare the microbial communities between polluted and non-polluted sites. In general, Proteobacteria was the most representative phylum in all sites. However, the clean water reference point was enriched with microorganism from the Limnohabitans genus, a planktonic bacterium widespread in freshwater ecosystems. Nevertheless, in the polluted sampled sites, we found a high abundance of potential opportunistic pathogen genera such as Acinetobacter, Arcobacter, and Myroides, among others. This suggests that in addition to water contamination, an imminent human health risk due to pathogenic bacteria can potentially affect a population of ∼1.6 million people dwelling nearby. These results will contribute to the knowledge regarding anthropogenic pollution on the microbial population dynamic and how they affect human health and life quality.

The aim of this study is to analyze the water quality parameters and bacterial diversity and thereby understand the effect of water quality on the microbial population structure in the river. The following parameters: total coliforms, chemical oxygen demand, harness, ammonium, nitrite, nitrate, total Kjeldahl nitrogen, dissolved oxygen, total phosphorus, total dissolved solids, and temperature were analyzing along 17 sampling points in the river. The worst levels of pollution were 510 mg/L chemical oxygen demand, 7 mg/L nitrite, 45 mg/L nitrate, 2 mg/L dissolved oxygen, and 756 mg/L of total dissolved solids. Whole metagenome shotgun sequencing was performed at 4 key points along the river (P1,P7,P10 and P17), the first point had clean water and the other points were polluted, as a result of this pollution, the structure of microbial communities along the river have changed. Proteobacteria and Bacteroidetes were the most representative phyla with a relative abundance of 57 and 43% respectively for P1, 82 and 15% for P7, 69 and 27% for P10 and 87 and 10% for the last point P17. P1 is rich in microorganism such as Limnohabitans a planktonic bacterium very common in freshwater ecosystems. However, in P7, P10 and P17 are rich in opportunistic pathogens such as Acinetobacter Arcobacter and Myroides that endangers the health of around 1.6 million people which live around the area. These results elucidate the influence of the pollution on the microbial community and the likely effects on the health of the people around.

The objective of this work was to evaluate the degradation of the nonionic surfactant Tween 80 by a PCE-degrading consortium anchored in bioparticles of fluidized bed bioreactors used in onsite remediation. Batch lab-scale bioreactors were set with dominant denitrifying (DN), methanogenic (M), and aerobic (Ab) metabolisms. Tween 80 at 100 mg/L was the sole source of carbon and energy. Denitrifying bioreactors had the highest surfactant removal (70%). Tween removals in M and Ab bioreactors were 53 and 37%, respectively. Removals of organic matter (COD) closely followed the efficiencies reported for Tween. This strongly suggested that degradation of Tween 80 occurred. Positive consequences of Tween degradation in remediation are first, the surfactant will not become an environmental/health liability by remaining as a recalcitrant or toxic substance in aquifers or in treated effluents; and second, savings on aeration could be achieved by conducting Tween 80 degradation in anaerobic conditions, either DN or M.

Agave tequilana bagasse is the main solid waste of the tequila manufacturing and represents an environmental issue as well as a potential feedstock for biofuel production due to its lignocellulosic composition and abundance. In this contribution, this feedstock was subjected to pretreatments with HCl and H 2 SO 4 for sugar recovery and methane was produced from the hydrolysates in batch and sequencing batch reactors (AnSBR). Sugar recovery was optimized by using central composite designs at different levels of temperature, acid concentration and hydrolysis time. Results showed that at optimal conditions, the HCl pretreatment induced higher sugar recoveries than the H 2 SO 4 one, 0.39 vs. 0.26 g total sugars/g bagasse. Furthermore, the H 2 SO 4 hydrolysate contained higher concentrations of potential inhibitory compounds (furans and acetic acid). Subsequent anaerobic batch assays demonstrated that the HCl hydrolysate is a more suitable substrate for methane production; a four-fold increase was found. A second optimization by using HCl as acid catalyst and methane production as the response variable demonstrated that softer hydrolysis conditions are required to optimize methane production as compared to sugar recovery (1.8% HCl, 119 °C and 103min vs. 1.9% HCl, 130 °C and 133min). This softer conditions were used to feed an AnSBR for 110 days and evaluate its stability at three different cycle times (5, 3 and 2 days). Results showed stable reactor performances at cycle times of 5 and 3 days, obtaining the highest methane yield and production at 3 days, 0.28 NL CH 4 /g-COD and 1.04 NL CH 4 /d respectively. Operation at shorter cycle times is not advised due to microbial imbalance.

The objectives of this work were first to evaluate the effect of coupling a zero-valent side filter to anaerobic fluidized bed bioreactors (HFBB) versus bioreactors without the zero-valent filter, also called methanogenic fluidized bed bioreactors (MFBB); and second to study the diversity of the microbial community in both types of bioreactors. At the end of operation (in the last 75 d), the HFBB reached a 95% removal of the incoming tetrachloroethylene, whereas the MFBBs without filter achieved a removal of 88%. Genera such as Dehalobacter spp., Desulfurospirillum spp., Desulfitobacterium spp., and Dehalococcoides spp., and Methanosarcina were found at the end of the treatment. Coupling zero-valent filters to bioreactors (HFBB) fed with high tetrachloroethylene concentration improved reactor performance [high tetrachloroethylene removal and reduction of concentrations of vinyl chloride (VC) and dichlorethylene (DCE)]. This performance was consistent with significant higher concentrations of dehal...