Publications by authors named "Cleotilde Juarez-Ramirez"

Groundwater and surface water bodies may have contaminants from urban, industrial, or agricultural wastewater, including emerging contaminants (ECs) or micropollutants (MPs). Frequently, they are not efficiently removed by microbial action due to their minimal concentration in water and the low microbiota affinity for complex compounds. This work developed a process allowing the adsorption of contaminants and their simultaneous biodegradation using horizontal tubular fixed-bed biofilm reactors (HTR).

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Purpose: The objective of the work is to determine the best operating conditions for variants of an ecological engineering tool (permeable reactive surface biobarrier -PRSB-) potentially useful for the protection of water resources, preventing the arrival of sediments and pesticides transported by runoffs and tile drainage from agricultural lands, to water bodies.

Methods: Four PRB-prototypes were constructed as fixed-bed horizontal channels packed with a porous material supporting an enriched microbial biofilm. Their dynamic and stoichiometric performance was evaluated in the presence or absence of granular activated carbon, with limiting or sufficient O supply.

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In 1995, Pseudomonas sp. ADP, capable of metabolizing atrazine, was isolated from contaminated soil. Genes responsible for atrazine mineralization were found scattered in the 108.

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The microbial corrosion of oil and gas pipes is one of the problems occurring in the oil industry. Various mechanisms explaining microbial corrosion have been demonstrated. Commonly, biocorrosion is attributed to sulfate-reducing bacteria.

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This study deals with the mathematical simulation and experimental validation of a gradient system for the gradual change of the imidacloprid loading rate to a tubular biofilm reactor (TBR). The strategy was used for fast studies of the kinetic and stoichiometric impact caused by the increase in the pesticide loading rate in a TBR, running in plug flow regime. Seemingly, this strategy has never been used for biokinetic and stoichiometric studies in biofilm reactors.

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Aromatic amines are important industrial products having in their molecular structure one or more aromatic rings. These are used as precursors for the synthesis of dyes, adhesives, pesticides, rubber, fertilizers and surfactants. The aromatic amines are common constituents of industrial effluents, generated mostly by the degradation of azo dyes.

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Tordon is a widely used herbicide formulation of 2,4-dichlorophenoxyacetic acid (2,4-D) and 4-amino-3,5,6-trichloropicolinic acid (picloram), and it is considered a toxic herbicide. The purposes of this work were to assess the feasibility of a microbial consortium inoculated in a lab-scale compartmentalized biobarrier, to remove these herbicides, and isolate, identify, and evaluate their predominant microbial constituents. Volumetric loading rates of herbicides ranging from 31.

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A microbial community, selected by its ability to degrade triazinic herbicides was acclimatized by successive transfers in batch cultures. Initially, its ability to degrade prometryn, was evaluated using free cells or cells attached to fragments of a porous support. As carbon, nitrogen and sulfur sources, prometryn, (98.

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In this work, an efficient degradation process for the removal of 2,4-D and ametryn, together with organic and inorganic adjuvants used in the commercial formulations of both herbicides, was developed. Although both compounds are toxic for microbial communities, ametryn is markedly more toxic than 2,4-D. In spite of this, the microbial consortium used could resist loading rates up to 31.

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The persistence of propanil in soil and aquatic environments along with the possible accumulation of toxic degradation products, such as chloroanilines, is of environmental concern. In this work, a continuous small-scale bioprocess to degrade the herbicide propanil, its main catabolic by-product, 3,4-dichloroaniline (3,4-DCA), and the herbicide adjuvants is carried out. A microbial consortium, constituted by nine bacterial genera, was selected.

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A microbial community able to aerobically degrade the azo dye Acid Orange 7 was selected from riparian or lacustrine sediments collected at sites receiving textile wastewaters. Three bacterial strains, pertaining to the genera Pseudomonas, Arthrobacter, and Rhizobium, constitute the selected community. The biodegradation of AO7 was carried out in batch-suspended cell culture and in a continuously operated multistage packed-bed BAC reactor.

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The main purpose of this work was to isolate and characterize lactic acid bacteria (LAB) strains to be used for biomass production using a whey-based medium supplemented with an ammonium salt and with very low levels of yeast extract (0.25 g/L). Five strains of LAB were isolated from naturally soured milk after enrichment in whey-based medium.

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