84 research outputs found

    Greenhouse Gases Production from Some Crops Growing Under Greenhouse Conditions

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    Greenhouse gases, such as carbon dioxide (CO2), nitrous oxide (N2O) and methane (CH4), play an important role in global climate change. For example, CO2 production occurs as a result of the seasonal cycles of the biotic processes of photosynthesis and respiration, as well as through anthropogenic activities and abiotic processes such as the burning of fossil fuels. Many activities, such as Agribusiness (the production of crops and animals for food) create greenhouse gases. Our research group has studied several soil treatments such as wastewater, wastewater sludge, vermicomposting, and urea among others, in order to study the effects of soil treatments on the production of greenhouse gases (CO2, N2O, and CH4) in several cultivars, but mainly in maize, sunflower and the common bean. The principal aim of this chapter is to show how these greenhouse gases are affected by the type of treatment, the properties of the soil, and the cultivar in question. We also look at which processes are involved in the production of CO2, N2O, and CH4 from cultivated soil. We present a review of several experiments carried out under in vitro or greenhouse conditions

    Bioactive compounds, antioxidant and antimicrobial activity of propolis extracts during In vitro digestion

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    The objective of this research was to determine the content of total phenols, total flavonoids, and the antioxidant and antimicrobial activity of the ethanolic extracts of propolis obtained by two methodologies during in vitro digestion. Ethanolic extracts of propolis were obtained by ultrasound and maceration and the yield and content of the bioactive compounds, as well as their antimicrobial and antioxidant activity, were evaluated. Yields higher than those reported in other investigations (71.6%) were obtained. The highest content of phenols and flavonoids in the ethanolic extracts was 34,406.6 mg GAE/100 g in propolis from San Pedro, obtained by maceration (SP M), and 19,523.2 mg QE/100 g in propolis from Teotitlán, obtained by ultrasound (TU), respectively, being higher than what is established in Mexican regulations. The antioxidant and antimicrobial activity of the extracts was not affected by the method of obtaining. At the end of the in vitro digestion there was an 80% loss of the phenolic content and a 90% loss of the flavonoid content. Therefore, antioxidant activity was affected. On the other hand, ultrasound improves the obtaining of bioactive compounds. In vitro digestion decreases the content of bioactive compounds; therefore, their functional properties are affected. Thus, it is important to consider technologies that allow extracts to be protected from in vitro digestion conditions.info:eu-repo/semantics/publishedVersio

    Heavy metal pollution in drinking water - a global risk for human health: A review

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    Water resources in the world have been profoundly influenced over the last years by human activities, whereby the world is currently facing critical water supply and drinking water quality problems. In many parts of the world heavy metal (HM) concentrations in drinking water are higher than some international guideline values. Discussing about the HM pollution in drinking water, the incorporation of them into the food chain, and their implications as a global risk for the human health, are the objectives of this review. It is known that there are million people with chronic HM poisoning which has become a worldwide public health issue, while 1.6 million children die each year from diseases for which contaminated drinking water is a leading cause. There is also evidence of HM in drinking water that are responsible for causing adverse effect on human health through food chain contamination. A global effort to offering affordable and healthy drinking water most to be launched throughout the world, while various laws and regulations to protect and improve the utilization of drinking water resources should be updated or created throughout the world, including the low income countries; otherwise, the problem of HM-polluted drinking water will be growing because demand for drinking water is still growing such as this problem will become even more pressing in the future. Finally, notwithstanding, additional researches are necessaries about the correlation between HM concentration in drinking water and human diseases, while the development of robust, cheap and sustainable technologies to improve the drinking water quality is necessary.Key words: Groundwater, aquifer, water quality, water pollution, microorganism, water supply, microbial communities, food chain, disease

    Why do microorganisms produce rhamnolipids?

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    Suitability assessment for electricity generation through renewable sources: towards sustainable energy production

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    Power generation through renewable sources is an effective alternative to mitigate climate change as its environmental impact is lower compared to fossil fuels. However, socio-economic problems are constant in sites where power plants are installed, especially in developing countries. In this paper, an innovative methodology was developed to assess the suitability of electricity generation through solar, wind, and biomass energy. Unlike most studies found in scientific literature, this work considers social, environmental, and economic aspects as key to determine the suitability of energy projects. First, we carried out a comprehensive analysis on social acceptance and resilience towards renewable energy and the conditions for communities to benefit from these projects; then, we analyzed the availability and capacity of renewable energy sources in Mexico, as a case study. Next,  a set of indicators related to the three pillars of sustainability was developed to assess the conditions of each place with the best renewable resources in the country. The life cycle and capacity factor of each technology were also considered. Lastly, a mathematical model was developed to determine the most suitable locations and technologies for power generation. The results show a trend towards the states of northern Mexico, especially those bordering the United States, as the most viable for electricity generation. The most appropriate technology is wind energy. Finally, Oaxaca, the state with the best wind resources and current leader in wind power generation in Mexico is, by contrast, the least viable state for wind generation, as has been later confirmed by scientific evidence, as wind facilities are associated with severe socio-cultural and economic damage in host communities in this state.La generación eléctrica mediante fuentes renovables es una alternativa eficaz para mitigar el cambio climático, pues su impacto ambiental es menor en comparación al de los combustibles fósiles. Sin embargo, hay problemas socioeconómicos constantes en los lugares donde se instalan las centrales eléctricas, especialmente en los países en desarrollo. En este trabajo, se desarrolló una metodología innovadora para evaluar la idoneidad de la generación de electricidad a través de energía solar, eólica y biomasa. A diferencia de la mayoría de los estudios encontrados en la literatura científica, este trabajo considera los aspectos sociales, ambientales y económicos como claves para determinar la idoneidad de los proyectos energéticos. Primero, se llevó a cabo un análisis sobre la aceptación social y la resiliencia hacia las energías renovables y las condiciones para que las comunidades se beneficien de estos proyectos, después, analizamos la disponibilidad y capacidad de las fuentes de energía renovable en México, como caso de estudio. A continuación, se desarrolló un conjunto de indicadores relacionados con los tres pilares de la sustentabilidad, para evaluar las condiciones de cada lugar con los mejores recursos renovables del país. También se consideró el ciclo de vida y el factor de capacidad de cada tecnología. Por último, se desarrolló un modelo matemático para conocer los lugares y tecnologías más adecuados para la generación eléctrica. Los resultados muestran una tendencia hacia los estados del norte de México, especialmente los limítrofes con Estados Unidos, a ser los más viables para la generación eléctrica. La tecnología más adecuada es la energía eólica. Finalmente, los hallazgos también indican que Oaxaca, el estado con los mejores recursos eólicos y líder en generación mediante esta tecnología en México, es el estado menos viable para la generación eólica, como fue confirmado con evidencia científica, ya que las instalaciones eólicas están asociadas con daños culturales y económicos en las comunidades receptoras en este estado

    Silver and Hematite Nanoparticles Had a Limited Effect on the Bacterial Community Structure in Soil Cultivated with <i>Phaseolus vulgaris</i> L.

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    The amount of nanoparticles that enters the environment has increased substantially in the last years. How they might affect plant characteristics and the bacterial community structure when they enter the soil, however, is still debated, as there is a continuous interaction between them. In this study, we determined the effect of silver (Ag-NPs) and hematite (α-Fe2O3-NPs) nanoparticles (0.15 g kg−1) on the characteristics of common bean (Phaseolus vulgaris L.) and the rhizosphere, non-rhizosphere and uncultivated soil bacterial community. The application of Ag-NPs or α-Fe2O3-NPs did not affect plant growth, but changed the amount of some heavy metals in the roots and aerial parts. The application of nanoparticles had a limited effect on the diversity, structure and functional profile of the soil and rhizosphere bacterial communities, but they were altered by cultivation of the bean plants and changed over time. It was found that application of Ag-NPs or α-Fe2O3-NPs had no effect on bean plant growth and only a small effect on the bacterial community structure and its putative metabolic functions. These findings show that in a complex system, such as a soil, different factors might affect the bacterial community structure and alter the possible effect of nanoparticles on it

    Bioactive Compounds of Opuntia spp. Acid Fruits: Micro and Nano-Emulsified Extracts and Applications in Nutraceutical Foods

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    The acid fruit of the "xoconostle" cactus belongs to the genus Opuntia family of cacti. It is used as a functional food for its bioactive compounds. Several studies reported that xoconostle fruits have a high amount of ascorbic acid, betalains, phenols, tannins, and flavonoids. These compounds confer antioxidant, antibacterial, anti-inflammatory, and hepatoprotective gastroprotective activity. Xoconostle fruit extracts were tested by in vitro assays where the digestion conditions were simulated to measure their stability. At the same time, the extracts were protected by encapsulation (microencapsulation, multiple emulsions, and nanoemulsions). Applications of encapsulated extracts were probed in various food matrices (edible films, meat products, dairy, and fruit coatings). The xoconostle is a natural source of nutraceutical compounds, and the use of this fruit in the new food could help improve consumers’ health

    Inhibition of Urease, Elastase, and β-Glucuronidase Enzymatic Activity by Applying Aqueous Extracts of Opuntia oligacantha C.F. Först Acid Fruits: In Vitro Essay under Simulated Digestive Conditions

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    Non-communicable diseases such as gastric inflammatory diseases and the hepatic pathologies are mainly related to bad lifestyle habits such as recurrent consumption of non-steroidal anti-inflammatory drugs (NSAIDs), excessive intake of alcohol, tobacco, steroids (high doses), alkaline agents, strong acid foods, and high-fat food, and Helicobacter pylori infections, among others. The fruit of Opuntia oligacantha C.F. Först var. Ulapa (xoconostle) is currently being studied due its nutritional and functional properties. The objective of the present study was to evaluate gastroprotective, anti-inflammatory, and hepatoprotective activities of different parts of xoconostle fruit by establishing in vitro simulated gastrointestinal conditions. Four treatments were established to test aqueous extracts (pericarp (P), mesocarp (M), endocarp (E) and whole fruit (W)). The quantified bioactive compounds were the total phenols, flavonoids, tannins, and betalains. The enzymatic assays were: urease, elastase, and β-glucuronidase. Significant differences (p &lt; 0.05) of bioactive compounds content were measured in xoconostle extracts, the highest concentration was found in W (phenols 313 mg GAE/100 g, flavonoids 189 mg QE/100 g, tannins 71 mg CATE/100 g). The betalains content was higher in E; 17 mg/100 g significant differences were observed (p &lt; 0.05) in the enzymatic inhibitions test (urease, elastase and β-glucuronidase), where W presented the highest inhibition activity (86%, 79%, and 84%), respectively. Bioactive compounds after in vitro gastrointestinal tests were maintained above 60% enzymatic inhibition activity

    Production of Kojic Acid by <i>Aspergillus niger</i> M4 with Different Concentrations of Yeast Extract as a Nitrogen Source

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    In agro-industrial processes, microorganisms that are not pathogenic and that generate molecules are generally recognized as safe (GRAS). The Aspergillus niger fungus has different industrial applications, being used to produce citric acid and 166 other secondary metabolites. The objective of this research was to optimize a culture medium to induce the production of kojic acid (KA) by the Aspergillus niger M4 strain in a liquid fermentation process. Four fermentative kinetics were developed in flasks, using different levels of yeast extract in (1) 0.05 g/L, (2) 0.10 g/L, (3) 2.5 g/L, and (4) 2.5 g/L + Zinc sulfate. The culture medium conditions influenced the formation and speed of biomass and the synthesis and yield of KA. The optimum production points were from 72 h and 96 h with 0.552 g/L and 0.510 g/L of KA using 2.5 g/L of yeast extract and with a pH of 5.5. The Aspergillus niger M4 strain had the ability to produce kojic acid, which was induced by the concentration of the nitrogen source

    Effect of pest-controlling neem and mata-raton on bean growth, soil N and soil CO2_{2} emissions

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    Extracts of plants such as neem (Azadirachta indica A. Juss.) and mata-raton (Gliricidia sepium (Jacquin)) are used to control pests. However, certain components of neem, such as azadirachtin, can exert a negative effect on fungi and nitrifying bacteria, and, in turn, can impact the C and N cycles in soil. Nutrient cycling might thus be inhibited and affect the sustainability of an agricultural system in which plant extracts are used to control pests. Here, we investigated the effect of neem extract on microbial activity and N mineralization in soil. We studied the effect of neem and mata-raton leaf extracts on bean growth (Phaseolus vulgaris L.).), nodule formation by Rhizobium, soil CO2_{2} emissions and soil N dynamics. Four treatments were applied: (1) "neem treatment": extracts of neem leaves, (2) "mata-raton treatment": extracts of mata-raton, (3) "chemical treatment": a chemical insecticide, lambda cyalothrin, and (4) "control": untreated plants. Our results show that in non-amended soil the number of nodules in the neem treatment was 18 for beans cultivated. This nodule number was 2.1 times lower compared with the soil treated with lambda cyalothrin (chemical treatment). In manure-amended soil, the number of nodules was 28 in the neem treatment. This nodule number was 1.6 times lower than in the mata-raton treatment. This indicated that neem extracts inhibited Rhizobium in soil and nodule formation in bean. In the manure-amended soil, the emission of CO2_{2} was 1.9 times lower in the neem-treated soil than in the other treatments. The increase in the concentration of NO3_{3}^{-} was 1.03 mg N kg1^{-1} soil day1^{-1} in the neem treatment and 4.1 times lower compared with the other treatments. As such, microbial activity was inhibited by the neem extracts when added to the manure-amended soil. It was found that application of neem leaf extract inhibited microbial activity and reduced nodule formation in bean, but lambda cyalothrin or leaf extracts of Gliricidia sepium did not
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