Co-presented by

Science vs paan stains: How a team from a Mumbai college has used genetic engineering to clean spatter

Paan stains are unarguably one of the most ubiquitous sights in India. Though governments past and present have launched cleanliness campaigns, this is one menace that doesn't seem to get tackled. From airports, to railway stations, to bus stops, to private residential complexes, schools, shopping malls, this red stain has made its way to almost every wall and corner in the country.

Chewing paan was once considered a custom of the aristocracy; kings and nobles employed servants who would carry spittoons. Habitual chewers of tambala would place spittoons within their houses "owing to the necessity of maintaining cleanliness in the home". But spitting in the open soon became a habit for many. Centuries later, people across social classes spit paan in outdoor spaces with abandon — without considering the effect this action has. People who travel in Mumbai's local trains are sure to have observed — and over time, turned oblivious — to stains outside the windows, on the doors and on the corners of the train's floor. While these stains are an eye-sore for commuters, it is the cleaners who face the real challenge of getting rid of them.

Cleaning these stains is no mean feat: It requires time, manpower, large quantities of water, and harsh industrial chemicals, effectively making paan stains not just a social menace but also an environmental challenge. A group of students from Mumbai, guided by their teacher, has found an environmental-friendly solution to this problem. Dr Mayuri Rege, biologist and teacher at Ramnarain Ruia College, led a team of eight undergraduate students — Aishwarya Rajurkar, Anjali Vaidya, Komal Parab, Maithili Savant, Mitali Patil, Nishtha Pange, Sanika Ambre and Shrutika Sawant — in the International Genetically Engineered Machines (iGEM) competition held in Boston. Assistant professors Mugdha Kulkarni, Sachin Rajagopalan, and Dr Anushree Lokur, HOD Microbiology and I/C Principal of Ruia College, were also part of this team. For their innovative research on removing paan stains using bio-engineered bacteria, they won a Gold Medal and a Special Prize for Best Integrated Human Practices.

 Science vs paan stains: How a team from a Mumbai college has used genetic engineering to clean spatter

Dr Rege and her team of students at the iGEM competition in Boston. Image via Facebook

Rege, who has a PhD from the University of Massachusetts Medical School and worked at the University of Pennsylvania as part of her postdoc degree in the US, joined Ruia College early in 2018. "I was brainstorming to come up with ideas to work on with the resources available at Ruia, but I didn't have much luck. The everyday commute constantly reminded me of the issue of paan stains — something I had forgotten after my stay abroad," recounts Rege. It was around the same time that the iGEM competition was announced and Rege felt it was the perfect opportunity to use her experience and motivate the students to think big. After considering all the ideas proposed by the students for the competition, it was decided, partly due to budgetary constraints, that they would try and tackle the issue of paan stains using genetic engineering principles.

Ruia's students made it to the list of five teams across India to secure Rs 10 lakh from the Department of Biotechnology (DBT) under the Ministry of Science and Technology and present their research at the iGEM competition. Rege says there were many challenges during the conceptualisation phase of the project, which was also the time when the students were learning core concepts in circuit design (in biology), applying what research had been done before to frame a unique approach. "Before we could begin our work, the other teachers and I had to train the students in how to do research. This included sound experimental design, recording their observations systematically and time management. Young researchers are easily demotivated when an experiment fails. We had to teach them to learn from their failures and understand the troubleshooting process, which is critical when you are doing research," mentions Rege.

Once their research objective was set and a concept was established, Rege and her students ventured out to gather samples for their experiment — in the streets and at paan sellers' shops. "Our hypothesis was that if we took samples from places laden with paan stains and cultured bacteria from them, anything that grows in that niche environment is also likely to feed on paan stains," Rege explains. She also explains how they had to formulate the food for the bacteria by getting feedback from the paan sellers and analysing the key ingredients of paan.


Organisms eating paan stains on a paan agar plate. Image via: Dr Mayuri Rege

Proteins purified from microorganisms that can decolourise paan stains (preliminary result). Image via: Dr Mayuri Rege

Proteins purified from microorganisms that can decolourise paan stains (preliminary result). Image via: Dr Mayuri Rege

"Using inputs from the paan sellers, we screened several isolates to find microorganisms that feed on the paan stains. One of them included the common bread mould!" says Rege, "Studying the chemical structure of the red compound in the paan stains, we predicted what proteins might degrade this colour. We then cloned our predicted proteins into harmless bacteria (E. coli strains routinely used in labs) to make large quantities of these proteins. When we tested these proteins on paan stains on various common surfaces, our results suggest that the predicted proteins do indeed attack stains and decolourise them."

Representing India at a global platform meant a great deal to both Rege and her students. "We had an incredible response from the judges as well as others who heard our work. In particular, they were impressed that we tried to solve a local problem that affected our everyday lives. Moreover, they appreciated how well we integrated the suggestions and requirements from all the stakeholders involved in our project to take it beyond just the lab," says a delighted Rege.

Winning these accolades has boosted the confidence of the entire team and strengthened their belief that undergraduate research can be a fun learning experience and, at the same time, positively impact society. After their winning streak in the iGEM competition, Rege says her team has been approached by the railways and several civic bodies who are extremely interested in their solution and look forward to using it. Some of these organisations have even offered full support to bringing Rege and her team's research experiment to fruition.

This enzyme-based cleaning method is an example of innovative, eco-friendly and cost-effective solutions to our everyday problems that greatly helps reduce the amount of water and money otherwise used to clean stains. However, given the nature of research, it is rather difficult to say when this product will be available in the market. But Rege is optimistic, "The work is in progress to translate our preliminary findings into a commercially usable and viable product. There are several issues we need to consider and test, such as which surfaces does the solution work on, its stability, large scale product cost and safety tests," she says.

Dr Mayuri Rege was a speaker at one of Junoon's interactive sessions titled 'Mumbai Locals: Science Vs Paan Stains' on 19 April in Mumbai's Kitab Khana

Your guide to the latest seat tally, live updates, analysis and list of winners for Lok Sabha Elections 2019 on Follow us on Twitter and Instagram or like our Instagram or like our Facebook page for updates from all 542 constituencies on counting day of the general elections.

Updated Date: Apr 27, 2019 14:29:01 IST