Biosorption of copper by immobilized biomass of Aspergillus australensis. Effect of metal on the viability, cellular components, polyhydroxyalkanoates production, and oxidative stress
2020
Contreras-Cortés, Ana Gabriela | Almendariz-Tapia, Francisco Javier | Cortez-Rocha, Mario Onofre | Burgos-Hernández, Armando | Rosas-Burgos, Ema Carina | Rodríguez-Félix, Francisco | Gómez-Álvarez, Agustín | Quevedo-López, Manuel Ángel | Plascencia-Jatomea, Maribel
Heavy metals are toxic especially when they are introduced into the environment due to anthropogenic activities such as metallurgy, mining, and tanning. Removing these pollutants has become a worldwide concern since they cannot be degraded into nontoxic forms causing extended effects in the ecosystems. The use of an Aspergillus australensis was evaluated in order to remove Cu²⁺ from simulated wastewater. The fungus was isolated from river sludges contaminated with heavy metals and was first evaluated for the determination of Cu²⁺ tolerance levels. Microscopic fluorescence analysis was carried out to determine the effect of Cu²⁺ presence on the viability, cellular components, polyhydroxyalkanoates production, and oxidative stress of the fungus, as a response to the stress caused by exposure to metal. In order to achieve copper removal, the A. australensis biomass was produced using batch cultures, and the mycelium was immobilized on a textile media in order to compare the copper-removal efficiency of live or dead biomass. The optimal values of pH and temperature for biomass production were established by using a surface response analysis. Live immobilized biomass was capable of removing Cu²⁺ from 1.54 ± 0.19 to 2.66 ± 0.26 mg of copper/ g of dry biomass, while values of 1.93 ± 0.03 to 2.36 ± 0.29 mg of copper/g of dry biomass were observed when dead biomass was used. As was expected, copper removal using biomass varied depending on the pH and temperature used.
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