Metallic Biosorption Using Yeasts in Continuous Systems

Mining effluents were found to be the main source of pollution by heavy metals of the surface water in the San Pedro River in Sonora, Mexico. The overall objective of this study was to determine the biosorption of Zn, Cu, Mn, and Fe with yeasts isolated from San Pedro River in a continuous system. The tests conducted in two reactors packed with zeolite connected in series. The first reactor was inoculated mixing two yeasts species, and the effluent of the first reactor was fed to second reactor. Subsequently, the first reactor was fed with contaminated water of San Pedro River and effluent from this was the second reactor influent. After 40 days of the experiment a reduction of 81.5% zinc, 76.5% copper, manganese 95.5%, and 99.8% of iron was obtained. These results show that the selected yeasts are capable of biosorbing zinc, copper, manganese, and iron under these conditions

Bioadsorption of copper and zinc with pre-treated and untreated dry biomass of Escherichia coli

Nowadays, new technologies are being developed for the removal of heavy metals, which are intended to have low operating costs and easy to implement. The copper and zinc bioadsorption in batch system was studies in pre-treated, with sodium hydroxide, and untreated Escherichia coli dried biomass. The E. coli was isolated and identified from water samples from the San Pedro river, Sonora, Mexico. The dry biomass of E. coli was pretreated with 0.1 N sodium hydroxide. The optimal biosorption conditions were at pH 5, 30 degrees C and 100 rpm. These studies demonstrated the effectiveness of the pre-treated biomass in determining the maximum bioadsorption capacity using the Langmuir model, and they were for copper of 204.49 mg/g and zinc of 151.97 mg/g, and for biomass untreated with copper and zinc were 107.52 mg/g and 125 mg/g, respectively. In addition, with the characterization by scanning electron microscopy and dispersive energy spectroscopy, the presence of copper and zinc were observed. The absorption bands by Fourier transform infrared spectrophotometry confirmed carboxyl, hydroxyl, amino and phosphate groups on the surface of E. coli. The use of dry biomass of pre-treated Escherichia coli in this study, showed to be effective in the bioadsorption process.Open access journalThis item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at [email protected]

GENERACIÓN DE BIOGÁS A PARTIR DE RESIDUOS ORGÁNICOS DEL COMEDOR DE LA UNIVERSIDAD DE SONORA

En este trabajo se evaluó el efecto de la biodegrabilidad anaerobia de los residuos sólidos orgánicos por medio de una biometanización para producir biogás como fuente de energía renovable. Para fines de este estudio se utilizaron los residuos sólidos de los alimentos provenientes del Comedor Universitario de la Universidad de Sonora. Las pruebas se realizaron por triplicado en botellas serológicas con volumen de operación de 120 mL, a las que se les adicionó cinco concentraciones de residuos (0.06, 0.12, 0.24, 0.6 y 1.2 gSVT), fueron inoculadas con biomasa metanogénica (0.24 gSSV) y se mantuvieron a 35°C por 30 días, la toxicidad de los residuos sobre la biomasa metanogénica se realizó con las mismas concentraciones pero se adicionó 5 g/L de acetato de calcio, por último se estudió el efecto del inóculo en cuatro proporciones diferentes de biomasa (0,1.66, 2.66 y 5.66 gSSV). Los resultados mostraron una producción de 71 m3 de metano por tonelada de residuos sólidos orgánicos el cual es superior al reportado en la literatura

Toxicological Assessment of Cross-Linked Beads of Chitosan-Alginate and <i>Aspergillus australensis</i> Biomass, with Efficiency as Biosorbent for Copper Removal

Sorbent materials of biological origin are considered as an alternative to the use of traditional methods in order to remove heavy metals. Interest in using these materials has increased over the past years due to their low cost and friendliness to the environment. The objective of this study was to synthesize and characterize cross-linked beads made of chitosan, alginate, and mycelium of a copper-tolerant strain of Aspergillus australensis. The acute toxicity of the biocomposite beads was assessed using brine shrimp Artemia salina nauplii and the phytotoxicity was determined using lettuce (Lactuca sativa) and chili pepper &#8217;Anaheim&#8217; (Capsicum annuum) seeds. The biosorption capacity for copper removal in simulated wastewater was also evaluated. Results showed that the biosorbent obtained had a maximal adsorption of 26.1 mg of Cu2+ per g of biocomposite, and removal efficiency was around 79%. The toxicity of simulated residual water after treatment with the biocomposite showed low toxicity toward seeds, which was highly dependent on the residual copper concentration. The toxicity of the biocomposite beads to A. salina was considered medium depending on the amount of the biocomposite, which was attributed to low pH. Biocomposite shows promise as biosorbent for the removal process of heavy metals