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Aims: The objective of this work was to determine the degradation capacity of low-density polyethylene by the bacterium Bacillus subtilis and analyze the production of extracellular laccase activity. Methodology: The experiments was realized in 50 mL of culture medium, added with a fragment of known dry weight (1 cm2 colorless polyethylene bag squares), and were incubated at 28°C, pH 6.5, for 6 months under static conditions, determining the growth of the bacterium by dry weight (68, 75, and 91 mg), the production of extracellular protein (271, 234, and 326.1 mg/mL), and the degradation of the substrate by dry biodegraded (8.57%, 5.88%, and 11.76%). Results: The production of extracellular laccase enzyme was analyzed in presence of polyethylene, finding an enzymatic activity of laccase of 2.06, 1.49, and 2,03 U/mL, while in the control without substrate, no enzymatic activity was observed, which suggests that this enzyme may participate in the degradation of polyethylene. In addition, some characteristics of the extracellular enzymatic activities were analyzed, such as stability at 4oC and 28oC, optimal pH and temperature, the effect of protein and substrate concentration. Conclusion: The extracellular protein production and dry weight of the bacterium are higher in the presence of low-density polyethylene. The laccase activity is very stable at 4oC and 28oC, the most effective pH and temperature, were 4.5 and 28oC, and present an incubation time of 5 minutes, and this data suggest that this enzymatic activitiy may participate in the degradation of low density polyethylene.

Recently, the removal capacity of different heavy metals from sites contaminated by low-cost materials has been studied, with promising results. These adsorbents include dead microorganisms, clay minerals, agricultural waste, industrial waste, and other materials. The objective of this work was studying the removal capacity of Cr (VI) by a commercial mushroom, the macromycete Agaricus bisporus (white strain), by the Diphenylcarbazide colorimetric method It was found that the biomass removal 100 mg/L of the metal at 21 minutes, pH 1.0, 28oC, and 100 rpm. On the other hand, if the concentration of the metal is increased, the removal capacity for the analyzed biomass decreases at 28oC. 200 mg/L are removal at 60 minutes, while with 1 g/L of the metal, its removal 90.3%. If the concentration of the bioadsorbent is increased, the removal of the metal also increases, and the presence of other heavy metals does not influence in the removal of the metal, and this was desorbed 70.4%, with NaOH 0.5 N. Finally, it was observing that after 7 days of incubation, 76.2%, and 66.1%, of Cr (VI) present in naturally contaminated earth and water, were removal, respectively.

Industrial effluents from chromium-based products lead to chromium pollution in the environment. Several technologies have been employed for the removal of chromium (Cr) from the environment, including adsorption, ion-exchange, bioremediation, etc. In this study, we isolated a Cr (VI)-resistant fungus, Purpureocillium lilacinum, from contaminated soil, which could reduce chromium. We also characterized a reductant activity of dichromate found in the cellular fraction of the fungus: optimal pH and temperature, effect of enzymatic inhibitors and enhancers, metal ions, use of electron donors, and initial Cr (VI) and protein concentration. This study also shows possible mechanisms that could be involved in the elimination of this metal. We observed an increase in the reduction of Cr (VI) activity in the presence of NADH followed by that of formate and acetate, as electron donor. This reduction was highly inhibited by EDTA followed by NaN3 and KCN, and this activity showed the highest activity at an optimal pH of 7.0 at 37 °C with a protein concentration of 3.62 µg/mL.

The biosorption of Co(II) on three fungal biomasses: Paecilomyces sp., Penicillium sp., and Aspergillus niger, was studied in this work. The fungal biomass of Paecilomyces sp. showed the best results, since it removes 93% at 24 h of incubation, while the biomasses of Penicillium sp. and Aspergillus niger are less efficient, since they remove the metal 77.5% and 70%, respectively, in the same time of incubation, with an optimum pH of removal for the three analyzed biomasses of 5.0 ± 0.2 at 28°C. Regarding the temperature of incubation, the most efficient biomass was that of Paecilomyces sp., since it removes 100%, at 50°C, while the biomasses of Penicillium sp. and Aspergillus niger remove 97.1% and 94.1%, at the same temperature, in 24 hours of incubation. On the contrary, if the concentration of the metal is increased, the removal capacity for the three analyzed biomasses decreases; if the concentration of the bioadsorbent is increased, the removal of the metal also increases. It was observed that, after 4 and 7 days of incubation, 100%, 100%, and 96.4% of Co(II) present in naturally contaminated water were removed, respectively.

Due to the increase in contamination of aquatic niches by different heavy metals, different technologies have been studied to eliminate these pollutants from contaminated aquatic sources. So the objective of this work was to determine the removal of cobalt (II) in aqueous solution by the biomass of the aquatic lily or water hyacinth (Eichhornia crassipes) which, is one of the main weeds present in fresh water, due to its rapid reproduction, growth, and high competitiveness, by the colorimetric method of the methyl isobutyl ketone. The removal was evaluated at different pHs (4.0–8.0) for 28 h. The effect of temperature in the range from 20 °C to 50 °C and the removal at different initial concentrations of cobalt (II) of 100 to 500 mg/L was also studied. The highest bioadsorption (100 mg/L) was at 28 h, at pH 5.0 and 28 °C, with a removal capacity of 73.1%, which is like some reports in the literature. Regarding the temperature, the highest removal was at 50 °C, at 28 h, with a removal of 89%. At the metal and biomass concentrations analyzed, its removal was 82% with 400–500 mg/L, and 100% with 5 g of natural biomass at 20 h. In addition, this completely removes the metal in situ (100 mg/L in contaminated water, at 7 days of incubation, with 10 g of natural biomass in 100 mL). So, the natural biomass can be used to remove it from industrial wastewater, even if in vivo, only eliminate 17.3% in 4 weeks.

Mercury (II) removal capacity in aqueous solution by Aspergillus niger biomass was analyzed by the atomic absorption spectrometry method. The fungus grew in 2000 ppm of the metal (20.3%). Biosorption was evaluated at different pH (3.5, 4.5, and 5.5) at different times. In addition, the effect of temperature in the range of 28°C to 45oC and removal at different initial concentrations of Hg (II) from 100 to 500 mg/L were also studied. The highest biosorption (83.2% with 100 mg/L of the metal, and 1 g of biomass) was 24 h at pH of 5.5 and 28oC. With regard to temperature, the highest removal was to 28oC, with an 83.2% removal at 24 h, and at higher biomass concentrations, the removal was most efficient (100% in 12 h with 5 g of biomass). Fungal biomass showed good removal capacity of the metal in situ, 69% removal in contaminated water, after 7 days of incubation and 5 g of biomass (100 mL water), so it can be used to remove industrial wastewater.

Chromium (VI) removal capacity in aqueous solution by oat biomass was analyzed by the diphenylcarbazide method. Bioadsorption was evaluated at different pH values (1, 2, 3 and 4) and at different times. The effect of temperature in the range of 28 °C to 60 °C and the removal at different initial Cr (VI) concentrations of 200 to 1000 mg/L were also studied. The highest bioadsorption (100% with 100 mg/L of the metal and 1 g of biomass) was at 8 h, at pH of 1.0 and 28 °C. With regard to temperature, the highest removal was to 60 oC, with a 100% removal at 90 min. Removal was more efficient when higher concentrations of biomass were used (100%, 3 h and 5 g of biomass). Untreated biomass (washed and ground biomass) showed excellent metal removal capacity in situ, 82.6% and 85.3% removal in contaminated soil and water, respectively, after 10 days of incubation, using 25 g of the biomass (100 mL of water). These results show that Cr (VI) can be removed from industrial wastewater using oat biomass.

A new proposal of biocompatible support, Mentha piperita aqueous and ethanolic extract decorated with silver nanoparticles, was successfully proved against C. albicans. Silver nanoparticles (AgNPs) with average size of 20 ± 3 nm, were synthesized to decorate both types of extracts, resulting in variations on the AgNPs distribution on the extract, depending on the solvent nature. The antimycotic activity of ethanolic extract exceeds aqueous extract by 89%, while decorated supports were 80% higher than without AgNPs. The activity of MpExtaq-AgNPs is lower than MpExtet-AgNPs since the nanoparticles are immersed in the extract, avoiding the action against C. albicans, whereas the MpExtet-AgNPs remain on the extract surface. C. albicans optical images showed dismembered cells without hyphae as a result of the treatment with MpExtet-AgNPs. As the MpExtet contains anthocyanins that were not found in MpExtaq, it is concluded that this secondary metabolite must play an important role in antifungal activity.

A natural and biocompatible extract of garlic as a support, decorated with silver nanoparticles, is a proposal to generate an effective antifungal agent against dermatophytes at low concentrations. Silver nanoparticles (AgNPs) with a diameter of 26±7 nm were synthesized and their antimycotic activity was examined against Trichophyton rubrum (T. rubrum), inhibiting 94 % of growth at a concentration of 0.08 mg ml-1 . Allium sativum (garlic) extract was also obtained (AsExt), and its MIC was 0.04 mg ml-1 . To increase the antifungal capacity of those systems, AsExt was decorated with AgNPs, obtaining AsExt-AgNPs. Using an AsExt concentration of 0.04 mg ml-1 in independent experiments with concentrations from 0.01 to 0.08 mg ml-1 of AgNPs, it was possible to inhibit T. rubrum at all AgNPs concentrations; it proves a synergistic effect between AgNPs and AsExt. Even if 1 % of the minimum inhibitory concentration of AsExt (0.0004 mg ml-1 ) is used, it was possible to inhibit T. rubrum at all concentrations of AgNPs, demonstrating the successful antimycotic activity potentiation when combining AsExt and AgNPs.

The objective of this work was to study the resistance and removal capacity of heavy metals by the fungusAspergillus niger. We analyzed the resistance to some heavy metals by dry weight and plate: the fungus grew in 2000 ppm of zinc, lead, and mercury, 1200 and 1000 ppm of arsenic (III) and (VI), 800 ppm of fluor and cobalt, and least in cadmium (400 ppm). With respect to their potential of removal of heavy metals, this removal was achieved for zinc (100%), mercury (83.2%), fluor (83%), cobalt (71.4%), fairly silver (48%), and copper (37%). The ideal conditions for the removal of 100 mg/L of the heavy metals were 28°C, pH between 4.0 and 5.5, 100 ppm of heavy metal, and 1 g of fungal biomass.

Los hongos se pueden comportar como alergenos, y si la concentración de esporas supera las 2.000 UFC/m3 son un factor de riesgo para la salud. Nuestro objetivo fue aislar esporas de hongos alergenos en una biblioteca. Para ello, se muestrearon 20 áreas, con el aparato Andersen de seis niveles, con cajas de Petri con agar sabouraud. Se aisló un total de 787 colonias, el 90.34% de hongos filamentosos y un 9.66% de levaduras. Los géneros aislados con mayor frecuencia fueron Cladosporium sp. (52.99%) y Penicillium sp. (13.34%), la temperatura y la humedad relativa promedio fueron de 24°C y 50% H. R., respectivamente. Se concluye que la concentración de esporas encontrada estuvo dentro de los límites aceptables de UFC/m3, sin embargo se sugiere mantener ventanas cerradas y hacer una adecuada limpieza de los espacios para evitar futuras complicaciones tanto en la salud de los usuarios como en el deterioro del material bibliográfico.

The biosorption of arsenic (V) on nine chemically modified biomasses (with iron oxide coated) of mycelia fungi: Aspergillus flavus III, IV and V, Aspergillus fumigatus I–II, Paecilomyces sp., Cladosporium sp., Mucor sp-1 and 2 was studied in this work. This study provides evidence that the biomasses of the fungi A. flavus, IV, III and V, Paecilomyces sp., and A. fumigatus I were very efficient at removing 1 mg/L of the metal in solution, using atomic absorption spectroscopy (AAS), achieving the following percentage of removals: 97.1, 92.3, 90.3, 89.0, and 83.4%, respectively. The results of adsorption were obtained at pH 6.0, 30 °C after 24 h of incubation, with 1 g/100 mL of fungal biomass. These results suggest the excellent potential of almost all isolated strains for bioremediation and removal of metals from contaminated sites.

espanolSe analizo la capacidad de remocion de arsenico (As V) en solucion acuosa por la biomasa modificada del hongo Aspergillus niger, por espectrometria de absorcion atomica. La contaminacion por arsenico es muy grave en Mexico, afecta a casi todas las poblaciones, y las tecnicas de remocion son muy caras y no tan eficientes. En los estudios, la mayor bioadsorcion (69% con 1 mg L-1 del metaloide) fue a las 24 horas, a pH de 6.0, 28oC y 1 g de biomasa modificada. Con respecto a la temperatura, la mas alta remocion fue a los 28oC, con un 69% de remocion a las 24 horas. A mayor concentracion de arsenico fue menor la remocion, y al aumentar la concentracion del bioadsorbente, la remocion es mas eficiente (96% con 5 g de biomasa). Ademas se remueve eficientemente el metaloide in situ (56% de remocion en agua natural contaminada con 1 mg 100 mL-1 de As (V) en 24 horas con 1 g de biomasa). Por lo tanto, la biomasa modificada se puede utilizar para eliminar el arsenico de aguas residuales industriales. EnglishThe removal capacity of arsenic (As V) in aqueous solution by the modified fungal biomass of Aspergillus niger, by atomic absorption spectrometry, was analyzed. Arsenic contamination is very serious in Mexico, it affects almost all populations, and the removal techniques are very expensive and not very efficient. In this study, the highest bioadsorption (69% with 1 mg L-1 of the metalloid) was at 24 hours at pH 6.0, 28oC and 1 g of modified biomass. With respect to the temperature, the highest removal was at 28oC, with a 69% removal in 24 hours. At higher concentration of arsenic the removal was lower, and by increasing the concentration of the bioadsorbent, the removal is more efficient (96% with 5 g of biomass). Additionally, the biomass efficiently removes the metalloid in situ (56% removal in natural water contaminated with 1 mg 100 mL-1 of As (V) in 24 hours with 1 g of biomass). Therefore, the modified biomass can be used to eliminate arsenic from industrial wastewater.

The biosorption of As(III) on iron-coated fungal biomass ofPaecilomycessp. was studied in this work. It was found that the biomass was very efficient removing the metal in solution, using Atomic Absorption, reaching the next percentage of removals: 64.5%. The highest adsorption was obtained at pH 6.0, at 30°C after 24 hours of incubation, with 1 mg/L of modified fungal biomass.

Fusarium solani is a necrotrophic parasitic fungus that causes wilt in some plants, causing severe economic losses in some areas of the country. The objective of this work was to analyze the induction of extracellular lytic enzymes produced by a strain of F. solani, isolated from a culture of tomato, in Villa de Arista, S.L.P. Mexico. Polygalacturonase activity has a greater induction time at 10 days, and the xylanase has two times higher activity at 8 and 13 days of incubation at 28?C. Also, the xylanase activities A and B were very stable at 4?C. After 7 days of incubation, it has an activity of 100% and 96%, respectively, while polygalacturonase retains 61% of its initial activity. Both activities are better induced with glutamate and urea as nitrogen sources respectively, and both exhibit an initial pH optimum of 5.5. Finally, we didn’t find cellulase activity in the analyzing conditions.

A chromium-resistant fungus isolated from contaminated air with industrial vapors can be used for reducing toxic Cr(VI) to Cr(III). This study analyzes in vitro reduction of hexavalent chromium using cell free extract(s) of the fungus that was characterized based on optimal temperature, pH, use of electron donors, metal ions and initial Cr(VI) concentration in the reaction mixture. This showed the highest activity at 37°C and pH 7.0; there is an increase in Cr(VI) reductase activity with addition of NADH as an electron donor, and it was highly inhibited by Hg2+, Ca2+and Mg2+, and azide, EDTA, and KCN.

Cr (VI) is a toxic metal, which belongs to the list of priority pollutants due to its mutagenic and carcinogenic properties, defined by the US EPA. Contamination comes from electroplating, leather tanning, textile dyeing and metal finishing industries. Recently, a variety of low cost materials has been studied for their ability to removal this metal from aqueous solution with promising results. We studied the removal capacity of Cr (VI) in solution by the Opuntia ficus-indica biomass, using the Diphenylcarbazide method to evaluate the metal concentration. Therefore, the highest biosorption of the metal (50 mg/L) occurs within 30 minutes, at pH 1.0, and 28°C. According to temperature, the highest removal was observed at 60°C, in 9 minutes, when the metal (50 mg/L) is completely adsorbed. At the concentrations of Cr (VI) and biomass analyzed, we observe an excellent removal capacity, besides, it removal efficiently the metal in situ (100% removal, at 6 and 7 days of incubation, 5 g of biomass, for water and earth contaminated), and after of 80 minutes of incubation, the studied biomass reduces 1.0 g of Cr (VI) with the simultaneous production of Cr (III), so it can be used to eliminate it from industrial wastewater.

We studied the Chromium(VI) removal capacity in aqueous solution by the lemon shell, using the diphenylcarbazide method to evaluate the metal concentration. So, the highest biosorption of the metal (50 mg/L) occurs within 100 minutes, at pH of 1.0, and 28°C. According to temperature, the highest removal was observed at 60°C, in 11 minutes, when the metal (1 g/L) is completely adsorbed. At the analyzed concentrations of Cr(VI), lemon shell, showed excellent removal capacity, besides it removes efficiently the metal in situ (97.2% removal, 7 days of incubation, 5 g of biomass). After 1 hour of incubation the studied biomass reduces 1.0 g of Cr(VI) with the simultaneous production of Cr(III); so it can be used to eliminate it from industrial wastewater.

Resumen Se aislaron diferentes microorganismos de varios rios de la Huasteca Potosina en Mexico, los cuales crecen en presencia de petroleo como unica fuente de carbono. Se determino la actividad de alcohol oxidasa por un metodo colorimetrico. La bacteria mas frecuentemente encontrada fue Pseudomonas aeruginosa (50%) y se encontro solamente una levadura, Candida albicans (6.25%). Ademas, presentan buena actividad de alcohol oxidasa en la fraccion citosolica con diferentes sustratos. Se concluye que estos microorganismos pueden ser utilizados para la eliminacion y degradacion de petroleo en sitios contaminados. Palabras clave: microorganismos, bacterias, contaminacion por petroleo, Candida albicans , alcohol oxidasa Isolation and Identification of Petroleum Resistant Bacteria and Yeast Abstract Different microorganisms were isolated from various rivers of the Huasteca Potosina, in Mexico that grow in the presence of petroleum as the sole carbon source. The activity of alcohol oxidase was determined by a colorimetric method. The most common bacteria present in the samples were

The objective of this work was to study the removal of chromium (VI) in aqueous solution by the fungus Penicillium sp. IA-01, isolated from polluted air with industrial vapors. To obtain the fungal biomass, pre-inoculums were performed in thioglycolate broth from a strain isolated from vapours contaminated with Cr (VI). The fungus was incubated for four weeks at ambient temperature, filtered, and washed three times with trideionized water. In preparing cellullar fractions, it was necessary to break the fungal cells with glass beads using a homogenizer being careful to keep the samples in frosty cold ice. To obtain the fungal biomass, the fungus was filtered and stored in an oven at 80°C, allowing it to dry for 48 h. Removal of Cr (VI) in vitro was evaluated using different cellular fractions and dead fungal biomass. We determine the optimal characteristics for metal removal in the reaction mixture. Concluding that the ideal conditions for the removal of Cr (VI) in the cell extracts were 37°C and pH 7.0, also we observ that the highest enzyme activity was in the mixed membrane fraction. In dead fungal biomass, the ideal conditions for removal of metal are 60°C and pH 1.0.

espanolEl objetivo de este trabajo fue analizar la capacidad de remocion de Cr (VI) por una cepa de Aspergillus niger, por el metodo colorimetrico de la difenilcarbazida. Cuando el hongo se incubo en medio minimo con glucosa y otras fuentes de carbono comerciales y economicas, como azucar no refinada o glicerol, en presencia de 50 mg/L de Cr (VI), removio totalmente el metal. Se produjo tambien Cr (III) en el medio de cultivo, despues de 6 dias de incubacion a 28°C, pH de 5.3 y 6.2, agitacion a una velocidad de 100 rpm y un inoculo de 8.3 mg de peso seco. Los resultados obtenidos indican que la cepa de A. niger tiene la capacidad de reducir Cr (VI) a Cr (III), y por lo tanto puede utilizarse para eliminar la contaminacion por Cr (VI). EnglishThe objective of this work was to analyze the capability a fungal strain of Aspergillus niger to reduce chromium (VI), using the colorimetric method of diphelylcarbazide. When the strain was incubated in minimal medium with glucose and other inexpensive commercial carbon sources such as unrefined sugar or glycerol, in presence of 50 mg/L of Cr (VI), the strain completely removed Cr (VI). Also, Cr (III) was produced in the growth medium after 6 days of incubation, at 28°C, pH of 5.3 and 6.2, agitation speed of 100 rpm and an inoculum of 8.3 mg of dry weight. These results indicate that the fungal strain of Aspergillus niger has the capacity of reducing Cr (VI) to Cr (III), and therefore it can be used in for reducing Cr (VI) pollution.

The purpose of this study was to identify and quantify non-structural carbohydrates in raw and hydrolysates juices, in stem and leaf that increase the sugars use from the plant and are a materials source for the mezcal agroindustry. We worked with maguey plants (Agave salmiana) from three maturity stages. High performance liquid chromatography (HPLC) for carbohydrates characterisation was applied. The determinations confirmed the presence of significant proportions of fructose, glucose and sucrose, and a lesser xylose and maltose proportion. The differences in carbohydrates concentration depend on studied factors as part of the plant, maturity state and thermal treatment (raw or hydrolysates juices). Therefore, technological and innovative actions to present synergies are necessary, for this reason, these treatments should be considered for better sugar content use and thus improve the use conditions that will maintain the environmental sustainability in the mezcal agroindustry development.

The biosorption of mercury (II) on 14 fungal biomasses,Aspergillus flavusI–V,Aspergillus fumigatusI-II,Helminthosporiumsp.,Cladosporiumsp.,Mucor rouxiimutant,M. rouxiiIM-80,Mucorsp 1 and 2, andCandida albicans, was studied in this work. It was found that the biomasses of the fungusM. rouxiiIM-80,M. rouxiimutant,Mucorsp1, andMucorsp 2 were very efficient removing the metal in solution, using dithizone, reaching the next percentage of removals: 95.3%, 88.7%, 80.4%, and 78.3%, respectively. The highest adsorption was obtained at pH 5.5, at 30°C after 24 hours of incubation, with 1 g/100 mL of fungal biomass.

The ability to reduce chromium (VI) by a fungal strain of Paecilomyces sp was studied. When it was incubated in minimal medium with glucose and other inexpensive commercial carbon sources such as unrefined and brown sugar or glycerol, in the presence of 50 mg/L of Cr(VI), the strain caused complete removal of Cr(VI). The reduction to Cr (III) occurs in the growth medium after 7 days of incubation, at 28°C, pH 4.0, and inoculum of 38 mg. Also, the fungi efficiently reduced the concentration of Cr(VI) from contaminated soil wastes. The results indicate that the fungal strain of Paecilomyces sp has the capacity of reducing Cr(VI) to Cr(III), and therefore it could be useful for the removal of Cr(VI) pollution.

Se aisló un hongo resistente y capaz de remover cromo hexavalente a partir del medio ambiente de una zona cercana a la Facultad de Ciencias Químicas, Universidad de San Luis Potosí en México. La cepa fue identificada como Paecilomyces sp, en base a sus características macro y microscópicas. La biomasa fúngica remueve eficientemente Cromo (VI) en solución y puede utilizarse para descontaminar nichos acuáticos contaminados, ya que 1 g de biomasa fúngica remueve 100 y 1000 mg/100 mL del metal a una y tres horas de incubación, y elimina totalmente 297 mg Cr(VI)/g de tierra contaminada.

Se aisló un hongo resistente y capaz de remover cromo hexavalente a partir del medio ambiente de una zona cercana a la Facultad de Ciencias Químicas, Universidad de San Luis Potosí en México. La cepa fue identificada como Paecilomyces sp, en base a sus características macro y microscópicas. La biomasa fúngica remueve eficientemente Cromo (VI) en solución y puede utilizarse para descontaminar nichos acuáticos contaminados, ya que 1 g de biomasa fúngica remueve 100 y 1000 mg/100 mL del metal a una y tres horas de incubación, y elimina totalmente 297 mg Cr(VI)/g de tierra contaminada. A fungal strain resistant to Cr (VI) and capable of removing the oxyanion from the médium was isolated from the environment near the Chemical Science Faculty, University San Luis Potosí in México. The strain was identified as Paecilomyces sp, by macro and microscopic characteristics. It was concluded that this fungal biomass can be used for the removal of Cr (VI) in aqueous solutions, since 1 g of fungal biomass removes 100 y 1000 mg/100 mL of this metal after one and three hours of incubation, and removes 297 mg Cr (VI) from contaminated soil.