ABSTRACT

The contamination of wastewater with metals and the use of biotechnologies to remove them is commonly discussed in theoretical biology, microbiology and biotechnology classes aimed at undergraduate students. This work introduces an easy, economical and safe practical laboratory class related to this topic. The practice consists in performing batch assays to remove Al(III) from aqueous solutions by using non-viable bacterial biomass trapped 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 colorimetric method. The data obtained are used to calculate and graphically represent the amount of metal adsorbed to the beads. Finally, students analyse and discuss the results to determine the optimal adsorption conditions. Moreover, since Al(III) becomes much more attached to beads with trapped biomass than to beads without microorganisms, the class serves to demonstrate one of the advantages of using immobilised microbial cells in adsorption processes. This class was satisfactorily implemented in an upper-level course for undergraduate students of biological sciences. They were able to properly execute all the experiments and calculations proposed and to become acquainted with useful experimental design to remove a metal.

摘要

在针对本科生的理论生物学、微生物学和生物技术课程中，经常讨论金属对废水的污染以及使用生物技术去除它们。这项工作介绍了与此主题相关的简单、经济且安全的实用实验室课程。该实践包括使用捕获在琼脂珠中的非活细菌生物质进行批量分析，以从水溶液中去除 Al(III)。学生准备这些珠子并根据以下因素分析 Al(III) 吸附：pH、接触时间和 Al(III) 浓度。游离 Al(III) 可通过简单的比色法通过分光光度法定量。获得的数据用于计算和图形表示吸附到珠子上的金属量。最后，学生分析和讨论结果以确定最佳吸附条件。此外，由于与没有微生物的珠子相比，Al(III) 更容易附着在带有捕获的生物质的珠子上，因此该类用于证明在吸附过程中使用固定化微生物细胞的优势之一。这门课在生物科学本科生的高级课程中得到了圆满的实施。他们能够正确执行所有提议的实验和计算，并熟悉有用的实验设计以去除金属。这门课在生物科学本科生的高级课程中得到了圆满的实施。他们能够正确执行所有提议的实验和计算，并熟悉有用的实验设计以去除金属。这门课在生物科学本科生的高级课程中得到了圆满的实施。他们能够正确执行所有提议的实验和计算，并熟悉有用的实验设计以去除金属。