Practical class to evaluate the adsorption of Al(III) ions from aqueous solutions using non-viable bacterial biomass trapped in an agar-agar matrix

BOERIS, PAOLA S.; BERGERO, MARÍA F.; HEREDIA, ROMINA M.; LIFFOURRENA, ANDRÉS S.; LUCCHESI, GLORIA I.

JOURNAL OF BIOLOGICAL EDUCATION

INST BIOLOGY

Año: 2020 p. 1 - 9

0021-9266

The contamination of wastewater with metals and the use of biotechnologiesto remove them is commonly discussed in theoretical biology, microbiologyand biotechnology classes aimed at undergraduate students. Thiswork introduces an easy, economical and safe practical laboratory classrelated to this topic. The practice consists in performing batch assays toremove Al(III) from aqueous solutions by using non-viable bacterial biomasstrapped in agar-agar beads. Students prepare these beads and analyse Al(III)adsorption on the basis of: pH, time of contact, and Al(III) concentration.Free Al(III) is quantified spectrophotometrically through a simple colorimetricmethod. The data obtained are used to calculate and graphicallyrepresent the amount of metal adsorbed to the beads. Finally, studentsanalyse and discuss the results to determine the optimal adsorption conditions.Moreover, since Al(III) becomes much more attached to beads withtrapped biomass than to beads without microorganisms, the class serves todemonstrate one of the advantages of using immobilised microbial cells inadsorption processes. This class was satisfactorily implemented in an upperlevelcourse for undergraduate students of biological sciences. They wereable to properly execute all the experiments and calculations proposed andto become acquainted with useful experimental design to remove a metal.