Tolerance of native Magellan fungi in peat to anthracene and n-dodecane for potential use in bioremediation

Tolerance of Magellan fungi in peat to anthracene and n-dodecane for potential use in bioremediation. Cien. Inv. Agr. 43(1):85-93. The tolerances of filamentous Magellan fungi in peat were analyzed in the presence of structurally different petroleum hydrocarbons to assess their abilities for bioremediation in contaminated soils. Fungi on PDA (potato dextrose agar) and fresh peat plates were cultured and purified. The morphologically identified species were grown in a hydrocarbon adapted-fungi (HAF) medium. Increasing concentrations of anthracene, n-dodecane and furfural were applied to observe tolerances based on the radial growth kinetics of hyphae. The results showed that the radial growths of hyphae in anthracene reached average speeds of 10.95 ± 1.21, 11.03 ± 3.14 and 10.96 ± 4.61 mm h-1 in 0.1, 1 and 2 g L"¹ solutions, respectively. The average growth rates in n-dodecane were 10.52 ± 3.33, 14.67 ± 1.88 and 10.86 ± 3.50 mm h-1 in 10, 20 and 40 g L-1 solutions, respectively. The growth rate in furfural reached 3.95 ± 1.07 mm/h in a 5 g L-1 concentration. The results suggest that the identified filamentous fungi are tolerant to anthracene and n-dodecane, which are the primary components of petroleum fractions. Furfural, a recognized antifungal, limited the growth. The results also indicate hydrocarbon degradation, suggesting that Magellanic peat can be used as a potential inoculum in bioremediation treatment processes associated with petroleum-contaminated soils. The observed filamentous fungi belong to the Penicillium genus based on visual identification and 18S rRNA.Tolerancia a antraceno y n-dodecano de hongos nativos de turba Magallánica para su potencial uso en biorremediación. Cien. Inv. Agr. 43(1):85-93. Se estudia la tolerancia de hongos filamentosos de turba magallánica en presencia de hidrocarburos derivados del petróleo estructuralmente diferentes, con miras a ser empleados como agentes de biorremediación de suelos contaminados. Se cultivaron y purificaron hongos en placas con PDA (Agar de Papa y Dextrosa) y turba fresca. Las especies morfológicamente identificadas se cultivaron en medio HAF (Hidrocarbon Adapted-Fungi) con concentraciones crecientes de antraceno, n-dodecano y furfural para observar su tolerancia a través de las cinéticas de crecimiento radial de hifas. Los resultados muestran que el crecimiento radial de las hifas en antraceno alcanzó una velocidad media de 10.95 ± 1.21, 11.03 ± 3.14, y 10.96 ± 4.61 mm h4 para concentraciones de 0.1, 1 y 2 g L4; para n-dodecano las velocidades medias alcanzaron los 10.52 ± 3.33, 14.67 ± 1.88 y 10.86 ± 3.50 mm h4 para 10, 20 y 40 g L4. Ensayos con furfural alcanzaron 3.95 ± 1.07 mm h4 a 5 g L4. Los resultados muestran que el hongo filamentoso identificado es tolerante a antraceno y n-dodecano, constituyentes característicos de fracciones del petróleo. Por su parte furfural, reconocido antifúngico, limita el crecimiento. Los resultados también muestran degradación de los compuestos señalados posicionando a la turba Magallánica como potencial contribuyente de inóculos para procesos de biorremediación de suelos contaminados con hidrocarburos del petróleo. Se identificó el género Penicillium como el hongo filamentoso desarrollado mediante identificación visual y 18S RNA

USE OF BIOSOLIDS AS FROTH REAGENT IN FLOTATION PROCESS: CHEMICAL AND PHYSICAL CHARACTERIZATION

Indexación: Web of Science; ScieloRESUMEN: La flotación espumosa usa diversos reactivos, orgánicos e inorgánicos, para aumentar el rendimiento y selectividad del proceso. La flotación utiliza sustancias tensoactivas que se adsorben en la interfase aire/agua. Como potenciales sustitutos de los espumantes usados actualmente, se consideran los residuos orgánicos de origen animal, como los biosólidos. Este estudio, evalúa el uso de biosólidos y ácidos húmicos como agentes espumantes para flotación espumosa, cuantificándose su capacidad tensoactiva y para formar y estabilizar espumas. Biosólidos son capaces de cambiar la tensión superficial de una solución, crear y estabilizar espumas. Dosis menores a 4 g L-1 muestran un afecto tensoactivo mayor comparado con reactivos espumantes, tipo MIBC. Para un uso efectivo de biosólidos, se requiere realizar una etapa de preacondicionamiento, que permita separar la fracción soluble y coloidal que tiene la capacidad tensoactiva. El uso de biosólidos a gran escala necesita investigación adicional para escalar los resultados obtenidos en laboratorio.ABSTRACT: Froth flotation uses various organic and inorganic reagents to increase performance and selectivity of the flotation process. Froth flotation takes place mediated by tensioactive substances that are adsorbed on the air/water interface. Potential substitutes for the currently used frothers, organic wastes of animal origin, like biosolids are found. This study was to evaluate biosolids and humic acids as foaming agents in froth flotation by quantification of their tensioactive capabilities, foam-forming potential and foam stability. Biosolids was able to change the surface tension of a solution, creating and stabilizing foams. Dosages under 4 g L-1 of flotation reagents showed a better tensioactive effect using biosolids instead of conventional flotation reagents, type MIBC. For an effective use of these substances as frothers, it is recommended to consider a preconditioning stage. That stage will permit separating soluble and colloidal fractions that show a tensioactive effect. Further research will be needed in order to scale-up current laboratory assays to operational mining scales.http://ref.scielo.org/y9j24

Hydrogen kinetics limitation of an autotrophic sulphate reduction reactor

Sulphate-reducing bacteria (SRB) are microorganisms that can be used as removal agents in polluted water sources. The use of inorganic substrates in SRB systems could reduce the cost and simplify operation. However, the use of H2 as an energetic substrate and the production of H2S as a metabolic product could produce kinetic limitations. The aim of this study was to assess the extent to which the kinetics of a sulphate reduction bioreactor was limited by its gas transfer capacity. Reactor kinetics were monitored by total pressure kinetics without sulphate limitation. It was concluded that the bioreactor design should be based on transfer properties. The uptake rate of H2 reached a maximum of 10-4 M/min, equivalent to a sulphate reduction rate of 3.4 g·L-1·d-1. The hydrogen mass transfer rate required a kLa of 1.48 min-1 at 1.2·109 cells/L in order to avoid limitation by H2 bio-availability (1.23·10-9 L·min-1·cell-1), which is a relevant value for scaling-up purposes

CO2 adsorption on agricultural biomass combustion ashes

Carbon capture and storage has become an alternative means of confronting global warming. Further research and development into adequate and low-cost materials is required for CO2 adsorption technologies.Samples of fly ash, bottom ash and their respective pellets, produced from wheat bran combustion, were characterized and tested to assess their capacity for CO2 adsorption at different temperatures. Neither the ashes nor their pellets were subject to prior thermochemical activation.The bottom ash sample and its pellets showed a higher adsorption capacity for the majority of the temperatures studied. The pelletized bottom ash reached the maximum adsorption capacity (0,07 mmol CO2/g), followed by the non-pelletized bottom ash (0,06 mmol CO2/g); both at an adsorption temperature of 25°C.CO2 adsorption of bottom ash, from the combustion of wheat bran (agricultural biomass), by a physical adsorption mechanism was demonstrated whereas with the fly ash sample, CO2 adsorption by both physical and chemical adsorption mechanisms was identified

Assessment of the flotability of chalcopyrite, molybdenite and pyrite using biosolids and their main components as collectors for greening the froth flotation of copper sulphide ores.

Biosolids and representative compounds of their main components ? humic acids, sugars, and proteins ? have been tested as possible environment-friendly collectors and frothers for the flotation of copper sulphide ores. The floatability of chalcopyrite and molybdenite ? both valuable sulphide minerals present in these ores ? as well as non-valuable pyrite was assessed through Hallimond tube flotation tests. Humic acids exhibit similar collector ability for chalcopyrite and molybdenite as that of a commercial collector (Aero 6697 promoter). Biosolids show more affinity for pyrite. The copper recovery (85.9%) and copper grade (6.7%) of a rougher concentrate obtained using humic acids as main collector for the flotation of a copper sulphide ore from Chile, were very similar to those of a copper concentrate produced by froth flotation under the same conditions with a xanthate type commercial collector. This new and feasible end-use of biosolids and humic acids should be new environment-friendly organic froth flotation agents for greening the concentration of copper sulphide ore. Now, further research is needed in order to scale current laboratory assays to operational mining scales to determine efficiencies to industrial scale

Bioremediation Of TOCs Present In Fuel-Contaminated Desert Mining Soil And Sawdust In The Atacama Region (Chile).

Repetitive small spills of fuel as diesel and lubricant oil during repair and maintenance of machinery as well as casual accidents within the mining industry constitute an unseen pollution of current environmental concern. The northern Chilean mining industry has not been an exception, where continuous fuel spills had occurred and had subsequently been adsorbed by desert soils and sawdust used as cheap sorbent materials to control environmental pollution. The resulting fuel-contaminated mixture is considered hazardous waste by the Chilean legislation, and thus contained in a hazardous waste landfill. Alternative options to landfilling and thus reduction of waste volume dumped in landfills consists of physical, chemical, and biological treatments or either combination, where bioremediation is a cost-effective alternative. Nevertheless, it remains unknown whether bioremediation of fuel-contaminated wastes is feasible under the environmental conditions of the Atacama region (Chile). In this study we determined the feasibility of bioremediation by aerated in-vessel composting of an aged fuel-contaminated desert mining soil and sawdust in the Atacama region. We investigated the removal of total organic compounds (TOCs) and changes in the microbial diversity during composting conditions at laboratory scale under controlled conditions of temperature, humidity and ventilation. Using biomolecular tools, we related contaminant removal to changes in the diversity of microbial communities

Photocatalyzed Production of Urea as a Hydrogen–Storage Material by TiO2–Based Materials

This review analyzes the photocatalyzed urea syntheses by TiO2–based materials. The most outstanding works in synthesizing urea from the simultaneous photocatalyzed reduction of carbon dioxide and nitrogen compounds are reviewed and discussed. Urea has been widely used in the agricultural industry as a fertilizer. It represents more than 50% of the nitrogen fertilizer market, and its global demand has increased more than 100 times in the last decades. In energy terms, urea has been considered a hydrogen–storage (6.71 wt.%) and ammonia–storage (56.7 wt.%) compound, giving it fuel potential. Urea properties meet the requirements of the US Department of Energy for hydrogen–storage substances, meanly because urea crystalizes, allowing storage and safe transportation. Conventional industrial urea synthesis is energy–intensive (3.2–5.5 GJ ton−1) since it requires high pressures and temperatures, so developing a photocatalyzed synthesis at ambient temperature and pressure is an attractive alternative to conventional synthesis. Due to the lack of reports for directly catalyzed urea synthesis, this review is based on the most prominent works. We provide details of developed experimental set–ups, amounts of products reported, the advantages and difficulties of the synthesis, and the scope of the technological and energetic challenges faced by TiO2–based photocatalyst materials used for urea synthesis. The possibility of scaling photocatalysis technology was evaluated as well. We hope this review invites exploring and developing a technology based on clean and renewable energies for industrial urea production

Multi-scenario energy-economic evaluation for a biorefinery based on microalgae biomass with application of anaerobic digestion

Microalgae are a source of biomass that has aroused the interest of the bioenergy industry due to its sustainability potential and maximum use of different abundant natural resources. This research proposes an energy-economic evaluation model for 11 scenarios for a biorefinery based on microalgae biomass, including a final stage of anaerobic digestion. Furthermore, it allows for comparisons between different scales of production, farming technologies and microalgae species, in line with latest industry information. Results are displayed by means of economic (NPV) and energy (EROI) indicators. Almost all the scenarios evaluated returned negative economic profitability, except for the extraction and commercialization of concentrated proteins (the PE scenario with protein sales of US$3/kg). In order to guide future research and investment in microalgae projects, a sensitivity analysis was conducted into the critical variables of the overall process. An optimistic context, led by the increase of the percentage of biomass lipids, allows a minimum biodiesel selling price to be reached which is close to the international value of fossil diesel (US$1/L) for scenarios in which this biofuel is commercialized.National Commission for Scientific and Technological Research (Comision Nacional de Investigacion Cientifica y Tecnologica, CONICYT) of the Chilean Government 22130431 Algae Fuels S.A. business consortium Chilean Economic Development Agency (Corporacion de Fomento de la Produccion, CORFO) Chilean Ministry of Energy via Renewable Energies Research Group of the Chemical and Bioprocess Engineering Department, of the Pontificia Universidad Catolica de Chile INNOVACORFO 09CTEI-686

Tolerance of native Magellan fungi in peat to anthracene and n-dodecane for potential use in bioremediation

The tolerances of filamentous Magellan fungi in peat were analyzed in the presence of structurally different petroleum hydrocarbons to assess their abilities for bioremediation in contaminated soils. Fungi on PDA (potato dextrose agar) and fresh peat plates were cultured and purified. The morphologically identified species were grown in a hydrocarbon adapted-fungi (HAF) medium. Increasing concentrations of anthracene, n-dodecane and furfural were applied to observe tolerances based on the radial growth kinetics of hyphae. The results showed that the radial growths of hyphae in anthracene reached average speeds of 10.95 +/- 1.21, 11.03 +/- 3.14 and 10.96 +/- 4.61 mm h(-1) in 0.1, 1 and 2 g L-1 solutions, respectively. The average growth rates in n-dodecane were 10.52 +/- 3.33, 14.67 +/- 1.88 and 10.86 +/- 3.50 mm h(-1) in 10, 20 and 40 g L-1 solutions, respectively. The growth rate in furfural reached 3.95 +/- 1.07 mm/h in a 5 g L-1 concentration. The results suggest that the identified filamentous fungi are tolerant to anthracene and n-dodecane, which are the primary components of petroleum fractions. Furfural, a recognized antifungal, limited the growth. The results also indicate hydrocarbon degradation, suggesting that Magellanic peat can be used as a potential inoculum in bioremediation treatment processes associated with petroleum-contaminated soils. The observed filamentous fungi belong to the Penicillium genus based on visual identification and 18S rRNANational Commission for Scientific and Technological Research (CONICYT) of the Chilean Government 21,090,47

Hydrogen kinetics limitation of an autotrophic sulphate reduction reactor

Sulphate-reducing bacteria (SRB) are microorganisms that can be used as removal agents in polluted water sources. The use of inorganic substrates in SRB systems could reduce the cost and simplify operation. However, the use of H2 as an energetic substrate and the production of H2S as a metabolic product could produce kinetic limitations. The aim of this study was to assess the extent to which the kinetics of a sulphate reduction bioreactor was limited by its gas transfer capacity. Reactor kinetics were monitored by total pressure kinetics without sulphate limitation. It was concluded that the bioreactor design should be based on transfer properties. The uptake rate of H2 reached a maximum of 10-4 M/min, equivalent to a sulphate reduction rate of 3.4 g·L-1·d-1. The hydrogen mass transfer rate required a kLa of 1.48 min-1 at 1.2·109 cells/L in order to avoid limitation by H2 bio-availability (1.23·10-9 L·min-1·cell-1), which is a relevant value for scaling-up purposesEl uso de sustratos inorgánicos podría reducir los costos y simplificar la operación de sistemas de tratamiento de aguas que utilizan bacterias reductoras de sulfato. Sin embargo, el uso de H2 como sustrato energético y la bioproducción de H2S podrían provocar limitaciones cinéticas. El objetivo de este estudio fue evaluar las condiciones en las que la capacidad de transferencia de masa de un bioreactor de reducción de sulfato, limita su cinética de reducción. La cinética del reactor fue obtenida monitoreando la presión del sistema en condiciones de no limitación por sulfato. Se concluyó que el diseño del bioreactor debería basarse en sus propiedades de transferencia. La tasa de consumo de H2 alcanzó un máximo de 10-4 M/min, para una tasa de reducción de sulfato de 3.4 g·L-1·d-1. Para evitar limitación por H2 se requirió un kLa de 1.48 min-1 a 1.2·109 cells/L (1.23·10-9 L·min-1·cell-1), valor relevante para propósitos de escalamient