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Learning bioreactor design using a frugal science approach

Tejaswini Pachpor

A laboratory can be a great place for experiential learning. But using set protocols and kits can deprive students of this opportunity and make them disengaged learners. In this article, an educator from Dr Vishwanath Karad’s MIT World Peace University, Pune shares a frugal science approach to provide experiential learning to her students and stimulate their creativity.

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A working model of a stirred-tank bioreactor to produce lemon-grass flavored kombucha, by Hritka Mehta, Sakshi Kumbhojkar, Sharvari Bhosale, Kavya Trivedi and Kiran Mitra. A plastic container was used as the main vessel. A plastic or metal stirring rod attached to the shaft of a small electric motor worked as the agitator inside the bioreactor. The small electric motor was fixed to the lid or top of the bioreactor vessel using hot glue or strong adhesive. The bioreactor was filled with the lemon grass liquid culture. The lid was attached securely to the bioreactor vessel to prevent spills. The small electric motor was attached to a battery pack to power the agitator.

It doesn’t matter how many resources you have. If you don’t know how to use them, it will never be enough”- Anonymous

We, as educators, talk about providing experiential learning to our science students. But to provide this experience, instead of letting them experiment with possibilities, we often hand them Standard Operation Protocols” or Kits’, which never allow them to fail. Do they really learn the science concepts we want them to learn this way? Do they think of innovative ideas in the laboratory? Being an undergraduate teacher for a decade, I have seen students beam with enthusiasm while entering the lab and leaving it disappointed due to a lack of creativity in the practicals.

On the other hand, engaging students in activities such as model making, fieldwork, etc., can not only stimulate experiential learning of the concepts involved, but also teach them basic science skills of creativity, observation, data collection, analysis, critical thinking, and problem-solving.

I teach at the Department of Bioscience and Technology, Dr Vishwanath Karad’s MIT World Peace University, Pune. This year, to invoke experiential learning, I asked the second-year students of Integrated BSc MSc Biotechnology to create working models of bioreactors using inexpensive and easily available objects.

In our theory classes, we had already discussed different bioreactor designs and their applications. The model-making activity would now challenge them to use the basic information they had learnt in class and build a model or a demonstration using readily available materials. I grouped the students into groups of 5 (we had 11 such groups) and gave them 1 month to come up with different models. I also asked them to submit a write-up explaining the following points:

  1. Product
  2. Bioreactor construction
  3. Biochemical reaction
  4. Observations/​learnings

In the course of the project, I helped them identify problems with their models and suggested modifications, if needed. By the end of the project, students came up with amazing working models that could explain the working of the airlift bioreactor, bubble reactor, and photobioreactor in the simplest manner. Students had prepared traditional rice sake, kombucha, and mead from kitchen supplies. I assessed the students based on novelty, originality, and execution of their models, along with their understanding of the concept.

This activity provided experiential learning to students in 4 stages:

  1. Experiencing: students recollected their experiences with fermentation, bioremediation etc.
  2. Reflecting: students reflected on how they could demonstrate the phenomenon in the form of a simple bioreactor model
  3. Thinking: students ideated on the design aspects of the bioreactor model
  4. Acting: students constructed the working model

This activity also stimulated creative problem-solving, which, at the heart of frugal science, focuses on delivering maximum value with minimal resources. Bioreactor design involves using specific geometry and dimensions of reactors to ensure the optimal growth of microorganisms. The students struggled to find the right container that would work as a bioreactor. They had to use inert materials.

Students Meetrayu Raut, Teertha Nambiar, Srushti Walvekar and Parnika Thakur were trying to use earthen pots to make rice sake. Nambiar took a traditional recipe for making the starter culture from her parents. In their first attempt at using earthen pots, most of the water was soaked up by the pot and the experiment failed. With lots of trials and errors, they could establish an actively growing culture and produce rice wine.

A working model of an airlift bioreactor for yeast biomass production, by Krishna Bangar, Kena Sojitra, Carolene Mathew and Samiksha Sonawane. A 1.5‑litre cylindrical plastic container measuring 19 cm in height and 5 cm in radius was used to build the yeast biomass production reactor, ideal for small-scale yeast cultivation experiments. Within the container, a plastic sheet measuring 8 – 9 cm in height was strategically placed to create two partitions, mimicking the airlift bioreactor design and facilitating nutrient circulation. Aeration was provided by an air pump connected via tubing to deliver a continuous stream of air into the nutrient medium, ensuring optimal oxygenation and nutrient mixing. To prevent contamination, surgical spirit (70% ethanol) was used to properly disinfect all equipment and the plastic container before inoculation.

Krishna Bangar, Kena Sojitra, Carolene Mathew and Samiksha Sonawane were working on constructing an airlift bioreactor, which requires circulation of compressed air. The challenge for this group was to control the air pressure. If the pressure is high, it would lead to frothing and loss of material; and if low, the biomass yield would be affected. After multiple attempts, they managed to control the airflow.

A working model of a photobioreactor for algal production, by Shivangi Singh, Ahan Sonar, Parnika Tayade, Prisha Yadav and Malay Raj Singh. A plastic container was washed properly and sterilised using steam. A hole was made in the lid of the container and the pipe of the air pump was inserted through it. Tiny holes were made around the sides of the lid for the passage of carbon dioxide out of the container during the growth of the algae. A string of LED lights was twisted circularly and stuck on the inner side of the lid with the help of a cellotape/​M seal to provide the light for the growth of algae.

The confident smile on the students’ faces while demonstrating the model to their peers and teachers arose from an understanding of the basic concept of the process.

When we design a syllabus, we pen down course outcomes and course objectives. This activity resulted in achieving an outcome – understanding a concept without using fancy equipment. The experiential learning approach gives students a chance to observe scientific phenomena around them keenly and learn by experimenting. Every trial-and-error attempt allows them to derive conclusions, from not only successes but also failures. When things do not work students proceed to think and ideate. In this activity, students were evaluated for the attempt, not just the result. This will encourage them to make more such attempts without fear of failing.