Búsqueda de capacidad productora de biosurfactantes en actinobacterias haloalcalófilas y haloalcalotolerantes

Una opción para biorremediar ambientes salinos contaminados con compuestos orgánicos hidrofóbicos, es el uso de microorganismos haloalcalófilos o haloalcalotolerantes capaces de producir biosurfactantes estables y consumir al compuesto hidrófobo. El biosurfactante solubiliza al contaminante haciéndolo biodisponible para el microrganismo. De estudios previos se conocía la capacidad de siete actinobacterias haloalcalotolerantes para transformar el antraceno. En este trabajo, a estas siete más 11 más aisladas de ambientes salinos, se les determinó la capacidad para producir biosurfactantes con propiedades emulsificantes. A las que la mostraron, fueron seleccionadas para saber si utilizaban al antraceno como única fuente de carbono y energía. La capacidad para producir biosurfactante fue determinada por los métodos de actividad hemolítica, gota colapsada y difusión del diámetro de la gota. La propiedad emulsificante y la estabilidad de la emulsión se caracterizaron con el índice de emulsificación y el índice de emulsificación relativo, respectivamente. De 18 actinobacterias evaluadas, cinco cepas mostraron capacidad para producir biosurfactantes con propiedades emulsificantes, alta estabilidad en la emulsión y utilización de antraceno como única fuente de carbono y energía. De estas cinco, dos son haloalcalófilas pertenecientes a la especie Nocardiopsis salina y tres son haloalcalotolerantes pertenecientes a las especies: Kocuria palustris, Microbacterium testaceum y Kocuria rosea. En un estudio previo se determinó la capacidad transformadora de antraceno en las tres cepas haloalcalotolerantes, por lo tanto los resultados de este estudio sugieren proponerlas como candidatas para procesos de biorremediación de ambientes salinos contaminados con compuestos hidrófobos. Asimismo se sugiere determinar la misma capacidad para las dos cepas haloalcalófilas.SIEA-UAEMex 3690/2014/CID SIEA-UAEMex 1039/2014RIFC SEP-PRODEP-Convocatoria de Redes 201

Haloalkalitolerant Actinobacteria with capacity for anthracene degradation isolated from soils close to areas with oil activity in the State of Veracruz, Mexico

The use of native strains of microorganisms from soils is an excellent option for bioremediation. To our knowledge, until now there has been no other group working on the isolation of Actinobacteria from contaminated soils in Mexico. In this study, samples of soils close to areas with oil activity in the State of Veracruz, Mexico, were inoculated for the isolation of Actinobacteria. The strains isolated were characterized morphologically, and the concentrations of NaCl and pH were determined for optimal growth. Strain selection was performed by the detection of a phylogenetic marker for Actinobacteria located at the 23S rRNA gene, followed by species identification by sequencing the 16S rRNA gene. Several haloalkalitolerant Actinobacteria were isolated and identified as: Kocuria rosea, K. palustris, Microbacterium testaceum, Nocardia farcinica and Cellulomonas denverensis. Except for C. denverensis, the biomass of all strains increased in the presence of anthracene. The strains capacity to metabolize anthracene (at 48 h), determined by fluorescence emission, was in the range of 46–54%. During this time, dihydroxy aromatic compounds formed, characterized by attenuated total reflectance Fourier transform infrared spectroscopy bands of 1205 cm–1 and 1217 cm–1. Those Actinobacteria are potentially useful for the bioremediation of saline and alkaline environments contaminated with polycyclic aromatic hydrocarbon compounds

Determination of the Residual Anthracene Concentration in Cultures of Haloalkalitolerant Actinomycetes by Excitation Fluorescence, Emission Fluorescence, and Synchronous Fluorescence: Comparative Study

Polycyclic aromatic hydrocarbons (PAHs) are compounds that can be quantified by fluorescence due to their high quantum yield. Haloalkalitolerant bacteria tolerate wide concentration ranges of NaCl and pH. They are potentially useful in the PAHs bioremediation of saline environments. However, it is known that salinity of the sample affects fluorescence signal regardless of the method.The objective of this work was to carry out a comparative study based on the sensitivity, linearity, and detection limits of the excitation, emission, and synchronous fluorescence methods, during the quantification of the residual anthracene concentration from the following haloalkalitolerant actinomycetes cultures Kocuria rosea, Kocuria palustris, Microbacterium testaceum, and 4 strains of Nocardia farcinica, in order to establish the proper fluorescence method to study the PAHs biodegrading capacity of haloalkalitolerant actinobacteria. The study demonstrated statistical differences among the strains and among the fluorescence methods regarding the anthracene residual concentration. The results showed that excitation and emission fluorescence methods performed very similarly but sensitivity in excitation fluorescence is slightly higher. Synchronous fluorescence using Δ = 150nm is not the most convenient method.Therefore we propose the excitation fluorescence as the fluorescence method to be used in the study of the PAHs biodegrading capacity of haloalkalitolerant actinomycetes

Mapping of the atmospheric deposition of sulfur and nitrogen during the dry season 2016 in the Metropolitan zone of Merida, Yucatan, Mexico

Abstract. Atmospheric deposition of sulfur and nitrogen was measured in the Metropolitan Area of Merida, Yucatan in Mexico during the dry season of 2016. Passive samplers type "throughfall" based on ion exchange resins were used to measure the hydrological flows in a total of 9 sampling sites distributed throughout the city. The ions retained in the resin were analyzed by turbidimetry and colorimetry to determine Ammonium, Nitrate and Sulfate. Deposition fluxes of S and N obtained were 6.25 and 5.19 Kg ha-1 yr-1. Both, sulfur and nitrogen atmospheric deposition fluxes were higher in urban sites, exceeding almost 2 times, the reference values proposed internationally for sensitive ecosystems. From the analysis of wind roses and air masses trajectories, it was possible to establish that during this climatic season, in addition to the local vehicular emissions, regional emissions generated upwind (from E-SE) contributed to atmospheric deposition of these ions. Finally, N and S deposition fluxes and their relationship with criteria pollutants were assessed, and maps for atmospheric deposition fluxes of Ammonium, Sulfate and Nitrate were generated using geo-statistical tools in order to identify critical deposition zones in this Metropolitan zone

Mapping and Estimation of Nitrogen and Sulfur Atmospheric Deposition Fluxes in Central Region of the Mexican Bajio

The objective of this study was to assess the spatial and temporal distribution of nitrogen and sulfur deposition and its relationship with meteorological conditions in the metropolitan area of León in Guanajuato, México. N and S atmospheric deposition was collected using passive samplers (IER) in 10 sites in León City during three climatic seasons in 2018. Nitrate, ammonium, and sulfate concentrations and deposition fluxes of N and S were determined. From wind and air-mass trajectories analysis, mechanisms and possible sources contributing to N and S deposition in the study area were assessed. Atmospheric deposition fluxes were compared to critical load values reported for sensitive ecosystems in Europe. It was found that mean deposition flux for N (5.82 Kg N ha−1 year−1) was within the range of values reported for sensitive ecosystems in Nuevo México, Europe, and California. On the other hand, the mean deposition flux for S (13.77 S Kg ha−1 year−1) exceeded the critical load values proposed for Europe, suggesting that current S deposition could be a risk for ecosystems and water bodies in the region

Short-term Effects of Air Pollution on Health in the Metropolitan Area of Guadalajara using a Time-series Approach

ABSTRACT This work have like purpose quantitative estimates of the short-term effects of air pollution on the health of residents of five municipalities of the Metropolitan Area of Guadalajara, Mexico from 2012 to 2015 using time-series approach. Air Quality was assessed for CO, NO2, SO2, O3 and PM10. Tlaquepaque had the highest mean concentrations for CO (0.88 ppm), NO2 (24.55 ppb), SO2 (0.0036 ppm) and PM10 (53.81 µg m–3), whereas, Zapopan registered the highest mean value for O3 (25.06 ppb). Only PM10 and Ozone exceeded the maximum permissible values established in the Mexican official standards. SO2 presented the highest RRI values in MAG, especially for Zapopan and Tonala, for the majority of the population: 0–59 years and > 60 years. Regarding to CO, excepting Guadalajara and Tlaquepaque, associations were not significant in the most of studied municipalities. The increase of risk as percentage for NO2 was 1.77% for 0–59 years in Guadalajara and Tlaquepaque, 1.87% by respiratory causes in Tlaquepaque, 1.73% > 60 years in Tonala, and 1.25% for 0–59 years in Zapopan. The association between daily mortality and increased O3 levels were significant, however, values were low for all studied municipalities. Finally, regarding to PM10, only Zapopan and Tonala showed statistical significance. This study cannot predict if reductions in criteria pollutants levels would have an important effect on a reduction in daily mortality, however, considering the large size of population exposed, even when observed associations were small but significant, RRI values found are of public concern. Keywords: Relative risk index; Mortality; Megacities; Criteria air pollutants; Mexico

Consistência interna e estrutura fatorial da Nova Escala Revisada de Paradigmas Ecológicos em estudantes universitários do sudeste do México

A nova Escala de Paradigma Ecológico revisada (NEP-R) traduzida para o espanhol é um instrumento amplamente utilizado em vários países, culturas e populações para medir as crenças ambientais das pessoas. Dada a discrepância em sua dimensionalidade relatada em estudos anteriores e como não há relatos de suas propriedades psicométricas da escala NEP-R na população universitária mexicana, eles foram analisados. A escala foi aplicada a 503 estudantes da Universidade Autônoma do Carmen, de diferentes entidades federais do sudeste do México. A consistência interna (α de Cronbach) da escala NEP-R foi analisada e uma análise fatorial exploratória (AFE) com rotação varimax foi realizada. A descoberta revelou um ótimo coeficiente de consistência interna (α = 0,702) e uma estrutura de dois fatores (ecocentrismo e antropocentrismo), que juntos representam 43,272% da variância total em uma versão da escala de 9 itens. Concluise que a escala NEP.R é uma ferramenta útil. No entanto, é imperativo avaliar sua confiabilidade e dimensionalidade para diferentes populações-alvo

BÚSQUEDA DE CAPACIDAD PRODUCTORA DE BIOSURFACTANTES EN ACTINOBACTERIAS HALOALCALÓFILAS Y HALOALCALOTOLERANTES

Una opción para biorremediar ambientes salinos contaminados con compuestos orgánicos hidrofóbicos, es el uso de microorganismos haloalcalófilos o haloalcalotolerantes capaces de producir biosurfactantes estables y consumir al compuesto hidrófobo. El biosurfactante solubiliza al contaminante haciéndolo biodisponible para el microrganismo. De estudios previos se conocía la capacidad de siete actinobacterias haloalcalotolerantes para transformar el antraceno. En este trabajo, a estas siete más 11 más aisladas de ambientes salinos, se les determinó la capacidad para producir biosurfactantes con propiedades emulsificantes. A las que la mostraron, fueron seleccionadas para saber si utilizaban al antraceno como única fuente de carbono y energía. La capacidad para producir biosurfactante fue determinada por los métodos de actividad hemolítica, gota colapsada y difusión del diámetro de la gota. La propiedad emulsificante y la estabilidad de la emulsión se caracterizaron con el índice de emulsificación y el índice de emulsificación relativo, respectivamente. De 18 actinobacterias evaluadas, cinco cepas mostraron capacidad para producir biosurfactantes con propiedades emulsificantes, alta estabilidad en la emulsión y utilización de antraceno como única fuente de carbono y energía. De estas cinco, dos son haloalcalófilas pertenecientes a la especie Nocardiopsis salina y tres son haloalcalotolerantes pertenecientes a las especies: Kocuria palustris, Microbacterium testaceum y Kocuria rosea. En un estudio previo se determinó la capacidad transformadora de antraceno en las tres cepas haloalcalotolerantes, por lo tanto los resultados de este estudio sugieren proponerlas como candidatas para procesos de biorremediación de ambientes salinos contaminados con compuestos hidrófobos. Asimismo se sugiere determinar la misma capacidad para las dos cepas haloalcalófilas

Atmospheric Levels of Benzene and C1-C2 Carbonyls in San Nicolas de los Garza, Nuevo Leon, Mexico: Source Implications and Health Risk

Atmospheric benzene and carbonyls were studied in San Nicolas de los Garza, Nuevo Leon, during 2011 and 2012. The relative abundance for measured VOCs was the following: formaldehyde (9.06 µg m−3) > acetaldehyde (8.06 µg m−3) > benzene (0.65 µg m−3). All measured VOCs had a clear seasonal trend with higher values of concentration during summer. Benzene and formaldehyde had a marked diurnal trend with the highest levels during morning, whereas acetaldehyde did not show a clear diurnal pattern. Meteorological analysis showed that the dominant winds came from NNE and ENE, suggesting that sources located in these directions contribute to the VOC levels. Principal component analysis (PCA) analysis revealed that photochemical activity influenced benzene and carbonyl levels during summer and that benzene was associated with vehicular traffic emissions during autumn and winter, showing good correlation with CO. Meteorological data showed that measured VOCs were influenced by regional sources. A health risk assessment showed that local exposure to carbonyls and benzene exceeded 1 × 10−6 for integrated lifetime cancer risk. People living in San Nicolas de los Garza, thus, have a probable risk of suffering cancer in their lifetime. It is, therefore, necessary to improve environmental policies for controlling VOC levels in this area

Short-Term Associations between Morbidity and Air Pollution in Metropolitan Area of Monterrey, Mexico

Short-term effects of air pollution on the number of hospital admissions in eight municipalities of the Metropolitan Area of Monterrey, Mexico, were assessed from 2016 to 2019 using a time-series approach. Air quality data were obtained from the Atmospheric Monitoring System of Nuevo Leon State (SIMA) which belongs to SINAICA (National System of Air Quality Information), providing validated data for this study. Epidemiological data were provided by SINAIS (National System of Health Information), considering admission by all causes and specific causes, gender and different age groups. Guadalupe had the highest mean concentrations for SO2, CO and O3; whereas Santa Catarina showed the highest NO2 concentrations. Escobedo and Garcia registered the highest levels for PM10. Only PM10 and O3 exceeded the permissible maximum values established in Mexican official standards. A basal Poisson model was constructed to assess the association between daily morbidity and air pollutants, from this, a second scenario in which daily mean concentrations of air pollutant criteria increase by 10% was considered. Most of pollutants and municipalities studied showed a great number of associations between an increase of 10% in their current concentrations and morbidity, especially for the age group between 5 and 59 years during cold months, excepting ozone which showed a strongest correlation during summer. Results were comparable to those reported by other authors around the world, however, in spite of relative risk index (RRI) values being low, they are of public concern. This study demonstrated that considering the nature of their activities, economically active population and students, they could be more vulnerable to air pollution effects. Results found in this study can be used by decision makers to develop public policies focused on protecting this specific group of the population in metropolitan areas in Mexico