Silvia Yudith Martínez Amador

Bioelectrochemical systems (BES) remove high concentrations of organic and inorganic contaminants and generate energy. It has been proven that they are more ef ficient when working with small-volume modules (such as stacks or cascades) than with a large reactor volume. In this work, the ef fect of hydraulic retention time (HRT) on the removal of chemical oxygen demand (COD), biochemical oxygen demand (BOD5), total solids (TS), total suspended solids (TSS), total coliforms (TC), fecal coliforms (FC), helminth eggs (HE), and power generation of a modular bioelectrochemical system consisting of ten dual-compartment microbial fuel cells (MFC) of 2000 mL each during the treatment of municipal wastewater (MWW) was assessed. The increase in HRT had a positive impact. In a 5-h HRT, the removal ef ficiency percentages of COD, BOD5, TS, TSS, TC, FC, and HE were 66.46, 34.18, 36.76, 53.84, 99.99, 99.99, and 91.88%, respectively. Likewise, at this same HRT (5 h), the highest maximum power density of 5.709 mW m-3 and the coulombic ef ficiency of 0.0056% were obtained. Results showed that the modular BES increases energy generation and contaminant removal, especially pathogens (TC, FC, and HE).

Natural biostimulants, such as microorganisms and seaweed extracts, are used in agriculture to improve crop yields with a sustainable approach. However, the interaction effects between different biostimulants have not been thoroughly investigated. The objective of this work was to evaluate the synergistic effects of microorganisms (Glomus intraradices and Azospirillum brasilense) and seaweed extract (Ascophyllum nodosum and Macrocytis pyrifera) on growth, yield and fruit quality of cucumber plants under soilless cultivation. Two doses of microorganisms (0 and 10 spores mL-1 + 106 CFU) and four concentrations of seaweed extract (0, 250, 500 and 2500 ppm) were evaluated. The experimental design used was a randomized complete block design with a factorial arrangement (2 x 4), with four replications per treatment. The results showed that the equatorial diameter of the fruit, yield and titratable acidity improve when applying microorganisms and seaweed extract in combination; however, when applying the two biostimulants the values ​​of plant height, stem diameter, number of leaves, root length, biomass (fresh and dry), firmness, total soluble solids, vitamin C, chlorophyll (a and total) and indices of color (L* and b*) did not exceed those obtained when the biostimulants were applied individually. The combined application of microorganisms and seaweed extract improves cucumber yield, but not vegetative growth and, except for titratable acidity, fruit quality attributes.

Swiss chard is a horticultural crop with a highly nutritious value. These crops’ production required nutrients, which can be provided through mineral nutrient solutions or biofertilizers. Biofertilizers are products that contain beneficial microorganisms that improve soil quality and that promote plant growth. Additionally, these microorganisms carry out nitrogen fixation and phosphate solubilization. The present work assessed the application of compost tea, co-inoculation (Azospirillum and Glomus), and inorganic fertilizer over the growth (roots, stem, and leaves) and nutrient content in Swiss chard (Beta vulgaris var. Forhook Giant) plants. The present work was carried out in a greenhouse using a randomized complete block design. Swiss chard plants treated with compost tea + inorganic fertilization (CTIF) accumulated more root and stem dry weight (4.06 and 8.10 g respectively), and, on the other hand, the leaf dry weight increased under three treatments: inorganic fertilization (IF), compost tea + co-inoculation (CTCi) and CTIF (12.5, 9.22 and 10.5 g respectively). Leaf area was greater in the IF and CTIF treatments. In Control (C) P and Mg content were higher; CTCi treatment increased the N, K, and Mn content; the co-inoculation (Ci) treatment increased Cu content as well as CTIF treatment increased the Ca, Fe, Zn, and B contents and in a lesser extent also the P, Mg, Cu, and Mn contents. The biomass partitioning coef ficient indicates that in six samples (from a total of seven samples), most of the photosynthates (PS) were used by the plants to form new leaves or to increase the size of the leaves. If an alternative method of fertilization is desired, it is recommended that a combination of biofertilizer and inorganic fertilization should be used, such as, the combination of compost tea and mineral solution that increased the production and the concentration of nutrients in the Swiss chard crop.

El agua residual municipal incluye efluentes provenientes de las residencias, la industria y el comercio; de estas aguas, sólo el 35.5% se lleva a tratamiento y una pequeña porción se reutiliza. El objetivo de esta investigación fue evaluar el crecimiento y desarrollo del cultivo de espinaca (Spinacia oleracea L.), irrigado con diferentes efluentes residuales. Los tratamientos aplicados fueron: agua residual sin tratar (ARST), agua residual tratada con sistema bioelectroquímico (ARTSB), agua residual tratada del Bosque Urbano de Saltillo (ARTBU), solución nutritiva Steiner (SS) y agua potable (AP). El diseño experimental fue de bloques al azar con 9 repeticiones por tratamiento, lo que da un total de 45 unidades experimentales; los muestreos se realizaron a los 15, 45 y 75 días de la siembra, y las variables de estudio fueron: número de hojas planta, longitud de raíz, longitud de tallo, área foliar y pesos secos de raíz, tallo y hoja. Los resultados del ANOVA y Prueba de Tukey (p> 0.05), mostraron que la longitud de raíz, el tratamiento con agua tratada del Bosque Urbano fue un 13.1% mayor al agua sin tratar, y el área foliar un 16.2% mayor. En los demás parámetros, el agua sin tratar estimuló el desarrollo, pero tiene efectos tóxicos para la planta. En conclusión, el agua residual tratada, al producir un incremento en la parte comercial de interés (la hoja), sería una opción recomendable para irrigar espinaca

Microbial electrosynthesis has gained much attention in the last decade in the scientific community due to that this novel process allows the production of commodity chemicals sustainably. MES (Microbial electrosynthesis cell), as commonly referred to as this technology, is a bioelectrochemical system that utilizes the reducing power generated from the anodic oxidation to produce high value-added products in the cathode. When coupled with a renewable source of electricity and organic or inorganic substances to produce biofuels, such as alcohols (ethanol, butanol, etc.), significant advantages stand out, such as the avoidance of fossil fuels to provide the energy that drives the 446process and food crops that serve as feedstock. The present chapter will give an insight into the novel perspectives of bioethanol production through bioelectrosynthesis as well as the more recent and relevant developments in MES technology for this purpose.

At present, civilization is facing several problems, being pollution and new energy sources at the top of the list. Billions of dollars are spent annually, to clean up the environment that has been polluted due to our diverse activities. Hence, the need to develop new technologies allows us to carry out this task with minimal energy consumption and high cleanup efficiency. In the case of wastewater, it can be treated sustainably with safety to minimize energy demand during the process, therefore maximize the recovery of valuable resources such as energy, water, and high value-added by-products. Bioelectrochemical system platform technology may carry out efficiently and at a lower cost the remediation process of different pollutants, compared to the traditional biological treatment. BES are capable of degrading diverse 254residuals or wastes, whereas the electrodes present in the BES serve as electron acceptors or donors and additionally the energy produced during the process may be used as an energy source for small devices.

Jatropha curcas L. hosts a wide variety of insects, but temporal variation in the composition of organisms (beta diversity) associated with crop farming has not been determined. Knowing the diversity and ecological role of its entomofauna are elements to develop management strategies for potential vulnerability of an agroecosystem. In this research, diversity, composition, and temporal turnover of insect species associated with cultivation of physic nuts were evaluated at Morelos, Mexico. During the second flowering period, 1,447 individuals in 13 orders, 106 families, 162 genera, and 190 species were collected; Hemiptera, Coleoptera, Diptera, and Hymenoptera comprised 89.9% of the individuals. Families Cicadellidae, Miridae, Chloropidae, Nitidulidae, and Chrysomelidae were most abundant. Insect alpha diversity, richness (0D), Shannon (1D), and Simpson (2D), did not show significant differences. Analysis of the composition of insect species using beta diversity (βSOR) showed a change of 0.37 ± 0.02 species. Piercing-sucking and chewing insects were the most diverse functional groups, of which at least 45 species are pests. The research should be complemented with more field observations in the Jatropha curcas crop. Results emphasized the need to consider different diversity aspects for appropriate crop management strategies.

Huitlacoche or corn smut, Ustilago maydis (DC.) Corda, is a biotrophic fungal pathogenic. The scales that grow in ears of maize, Zea mays L., are used as fresh or raw vegetables. In some regions of Mexico, maize is planted to harvest “huitlacoche”, a crop also susceptible to attack by insect pests that affect its quality. The purpose of this study was to recognize entomofauna in maize ears infected with huitlacoche (corn smut) and identify pest species that attack huitlacoche in five maize hybrids. We collected a total of 515 specimens in four orders, seven families, and 11 species. The orders Coleoptera and Lepidoptera comprised 71.4% of the total number of families, 81.8% of the species, and 99.6% of individuals. The percentage of damaged ears ranged from 47.5 to 65.0%. Species best represented were Cotinis mutabilis (Gory and Percheron), Spodoptera frugiperda (J.E. Smith), Heliothis virescens (Fabricius), and Carpophilus lugubris Murray considered primary pest of huitlacoche because they were present in all maize studied. Shannon-Wiener diversity (0.592 bits per individual) and Simpson (0.302 bits per individual) indices showed less diversity of individuals and moderate species dominance. Greatest richness of species was in hybrids ‘AN388’ and ‘H-318’, each with seven.

Purpose: Roses are one of the ornamental species of major importance and economic value. Fertilisation programmes which maximise plant growth and quality, while minimising environmental impact are important. Here, we followed the N and K dynamics during rose development with the aim to define the nutrient demands as a basis for implementing fertigation programmes. Materials and methods: Roses with one basal break were grown in a closed hydroponic system. Destructive samples were taken to determine dry weight, N and K content. In each sample, plants were sectioned into roots, rootstock, basal break, stems and leaves from the zone of active leaves and the zone of cutting flowers, as well as the flower bud in the latter. Results: The shoots of the active leaves and cutting flowers zones exhibited a biphasic growth; dry weight, N and K increased after pruning of the zone of active leaves and the cutting flowers zone, however, in the second phase, total dry weight did not show a significant difference between the phenological phases, while the accumulation of N and K decreased throughout the entire plant. Conclusions: Our results suggest that greenhouse roses develop a dynamic and complex balance between the aerial parts of the plants and the roots for storage and/or transport of photoassimilates, N and K. The total demand for N was 411 and 799 mg per plant for the initial shoot development of the active leaf zone and cutting flowers zone, respectively. The demand for K was 149 and 106 mg per plant for both shoots, respectively. The loss of N (555 mg per plant) and K (167 mg per plant) from roses plants to the root environment implies that lower fertiliser inputs can be used as these nutrients may be re-uptaken by new emerging roots.