Redesign of an Undergraduate General Microbiology Lab to Include Authentic Discovery-Driven Research on Cucumber Fermentations

Abstract

8Many undergraduate introductory microbiology laboratory courses teach basic principles of bacteriology using 9 classical protocol-based experiments, with limited critical thinking and inquiry-based learning practices. We 10 initiated a comprehensive redesign in our General Microbiology Laboratory course to promote scientific critical and 11 creative thinking, while strengthening core microbiology concepts and skills. As part of the redesign, a series of 12 authentic discovery-driven labs, based on cucumber fermentations, were developed as an independent research 13 module within the course curriculum. Integrating discovery-driven labs allowed students to be engaged problem 14 solvers, applying the scientific process to develop hypotheses, design experiments, utilize quantitative reasoning, 15 and effectively communicate results. The inquiry-guided research project was developed to evaluate the minimum 16 concentration of salt (NaCl) required in fermentation brine to safely, and effectively, ferment cucumbers. Over 5 17 weeks, students assess different aspects of the fermentation process, including quantifying bacterial populations with 18 differential and selective media, measuring pH and glucose concentration of brine solutions, and characterizing the 19 microbial metabolic potential. Additionally, students isolate an unknown bacterium from their fermentations, 20 identifying and characterizing the isolate using 16S rRNA gene sequencing and metabolic tests. Throughout the 21 research project, students collect, graph, and analyze their observations, culminating in students creating and 22 presenting a scientific research poster. With this lab redesign, students generate new knowledge contributing to our 23 understanding of microbial ecology within food fermentations, learn core microbiology skills and techniques, and 24 develop critical and creative thinking skills. The impact of their research is valuable to science educators, 25 researchers, and industry partners.26 27 fermentations; pickles for upper-level undergraduate students. Instruction in basic microbiological laboratory skills including aseptic 32 technique, bacterial isolation (T-streak and dilutions), biochemical and physiological characterization of bacteria, 33and staining and light microscopy are covered. Before this lab redesign, these skills and concepts were taught using 34 traditional protocol-based experiments with limited inquiry or critical and creative thinking, using the classic 35 identifying an unknown bacterium project 1 . A major goal of this course redesign was to actively engage students in 36 the creative process of scientific inquiry by incorporating authentic research into the curriculum. This type of 37 learning environment more closely resembles a modern research lab and creates an excitement for scientific inquiry, 38 striving to keep students in their academic trajectories as STEM majors, as well as preparing them for future 39 scientific careers. Furthermore, this redesign aims to increase student understanding of core conte...

Increasing student interest with the Bacterial Unknown Identification Project: using mixed cultures to create real-world applications

“…Modified approaches to the BUIP have been developed that include isolation of microorganisms from the environment that necessitate using molecular techniques because the organisms are truly unknown ( 4 – 6 ). These approaches, while useful in small classrooms of upper-division students, are difficult to implement in lower-division courses due to the large number and diversity of students.…”