Mariana Matus- The Hidden Value of Poop!

Growing up with constant water shortages made her truly value this precious resource, which is at the heart of life. Days without water were always stressful. Things many of us take for granted like food preparation, sanitation or taking a shower when it is hot required a lot of extra planning and took time away from other activities. Her work with residual water has taken her to the labs of UNAM (the National University of Mexico), Wageningen University in the Netherlands, Cambridge in the UK and now the MIT. Meet Mariana Matus, the Mexican computational and systems biologist whose life purpose revolves around the circular economy of water and the hidden treasures of our sewages.

When did you decide to become a scientist?

I thought maybe I would study medicine, mechanical and electric engineering or even business. I always loved mathematics and computing but I had no idea what I would study until literally days before I entered university.

Truth be told, I had no idea that scientific research was a profession. I knew no one who was a scientist and I had no access to internet as a child. So I discovered my profession only after I enrolled in University for Genomics, simply because the syllabus looked so interesting. I wasn’t thinking when I chose my degree of my career afterwards.

My degree at the National University of Mexico (UNAM) was very research heavy and I found Genomics very interesting. The first couple of years were hard. I moved far away from the family to a new city for me, Cuernavaca, where the program was based.

My field of study is evolving fast and is built on the huge advances of digitization and quantitative biology. It is a fascinating area as I get to work with people from many different fields such as mathematicians, programmers, architects and engineers.

Tell me about your childhood

I spent my early childhood in Mexico City, which is one of the world’s most populated cities. Nature was very far and my parents felt it was not safe to let us play outdoors. My sister and I had to be very ingenious about how to spend time after school. We adopted pets.We had dogs, cats, rabbits, a parrot, a rooster… simultaneously. It was a little insane and a lot of fun. I really enjoyed observing them trying to understand them and also their interaction.

My mother was an English teacher and she used to tutor kids at home. I enjoyed watching the classes, especially observing the learning process. We also used to play in English as part of the lesson so that was fun too.

In my teenage years we moved to San Luis Potosí, to follow my dads work. I am very grateful for my childhood.

You grew up in a city with water shortages. How did that shape you?

 When water is always available we don’t realize how important water is to our lives. There are many things you can do without and you can be OK after all. But water is not one of them: You need to shower, go to the bathroom, wash your hands before you eat, drink water. Getting clean water and disposing of dirty water is an accomplishment of many years of technology and it is not trivial. But in San Luis, water is available only on scheduled days. In the driest periods, even that is a luxury and one depends on water trucks to deliver it.  Water is a constant source of stress and it drives people to compete over it. Those days you simply cannot function normally. A lot of energy goes into coping around the shortage.

I worry that as water shortages continue to develop in the world, the availability of water will be determined by economic circumstances. I worry water may one day not be evenly distributed. For me, it is clear that we need to develop a more circular economy of water so that less water is wasted and it is available to all.

How on earth did you sewers become your passion?

I have been interested in sewage for a long time! My masters thesis was about sewage. What cleans the water in sewage treatment plants are microbes that are already in our guts, but react to temperature and chemicals in the treatment plants. I have studied the microbe communities that live in the treatment plants so that we can make improvements to the cleaning process of the water.

From doing all my research I know we know a lot about water treatment. But the process for treating water is very energy demanding and we could do much more to improve energy consumption and even to produce energy from sewage. For that reason I am also interested in bio energy. For instance, methane is produced as an outcome of the bacterial process of water cleaning that can be used for electricity generation. Phosphorous and nitrogen can also be recycled from sewages and used as fertilizers for instance. And of course, people are not aware of this but a lot of the water we consume is treated waste-water. So as you can see, there is a lot of value trapped in the sewage!

What are you working on now?

The latest project I am working on, Underworlds, started when the architects and engineers at MIT reached out to our faculty. They saw sewages as the ultimate collaborative source of data we have as everyone contributes to it and were looking for biomarkers that would give us a view of the whole population.

Many of the other biologists in the lab were skeptical but this made a lot of sense to me having looked at sewage for some many years. The idea that there is value in the sewage, even before the recycling process is very appealing to me. We can capture a lot of relevant information about our health and behaviors in the sewage.

Why are sewers such a good source of information?

We can learn a lot about population. Different disciplines come together and we are running two projects in parallel and collaborating on the design principles.

One of these, which I lead, develops the genomics methods needed to reliably detect bacteria, viruses and metabolites. We want to figure out how to for instance identify viruses and bacteria developing before there is a big outbreak.

The other line of work looks at the in situ collection sensors that could help us gather information live and on real time. We will be able to do that without having to gather samples. Once we have an automated system, we can tap into information all the time.

Could we eventually detect Ebola or Zika in the sewers before an outbreak?

We could measure two types of things in sewers.

One would be things that you expect to be always negative, such as ebola. If any of these unexpected things were positive, that would be very significant and should result in action. About 80 countries today employ systems like this for Polio. This is important because as only 1% of children who contract polio have symptoms, once you have 1 paralysis there are other 99 infected children. In contrast because Polio is a disease that reproduces in the human gut 96% of infected children shed polio in their faeces. Sewage research for Polio prevented a major outbreak in Israel and Egypt in 2013 because affected areas were given vaccinations in time to contain its spread. It would make sense to measure Ebola in the same way.

Another application would be to detect unusual chemicals that one is not expected to find in sewage. Finland was one of the pioneers of Polio research in the 1980’s and now Finland is innovating in detecting threats to social security.

We could also look for biomarkers of things that occur every year. In this case we could get a wealth of information beyond presence or absence. For instance, every year we know there will be a Norovirus outbreak. Here what sewers could help us with is to quantify trends, compare one year to another, look at the genetics of the virus and whether it is mutating or to study its strength.

Historically waste-water has been used for illicit drugs surveillance and finally as mentioned, the EU has a big project to detect bomb making chemicals, so it can be used for bio security.

If this technology has been available since the 1980’s why haven’t we seen more scientific advancement until now?

Usage of this technology has been niche as in the Polio case, because samples were taken manually and sporadically, as in monthly sampling. Having people sampling and running around with waste-water in a city is not scalable! But with robotics and digitalization we can now go much further, beyond Polio.

Having sensors in sewage will help us also with information about the sewage system itself and monitor how well it works from an engineering and architectural perspective. It would help us with expanding quality control metrics.

In the future, we could also expand the biological quality control metrics. Nowadays the metrics used are for bacterial content but they don’t measure other things like the presence of chemicals, pharmaceuticals or other substances in the sewage.

As populations are different, beyond epidemiological research we will also be able to understand the variables in different populations and implement different solutions in different places for different problems.

This sounds like an area where a lot of innovation is about to happen and I can see a space for wealth generation too for the communities. 

I think so too. We are in very early stages but there will be a lot of applications. We are talking to people in the city of Boston and one potential project would be to collaborate with the city on a number of projects. 

What have you found out about MIT sewers?

We just started this project to test our methodologies and will sample every two weeks. To begin we are looking at caffeine usage and their correlation to finals!

I can see there could be valuable information about demographics. In the future, we could look and compare demographics (socio-economic variables for instance) and maybe even bio locations (such as schools, old people’s homes, airports). There could be different applications for different uses.

In Project Underworlds you are working in a team made up of people from different backgrounds. There are architects, biologists, designers, electrical engineers, geneticists, and microbiologists. Talk to me about collaboration.

Biology is a field that is attracting many people lately from other fields. There is enormous value and a lot of potential for collaboration. Very good questions can be posed from people from other areas that allow us to look at biology differently. Maybe you thought you had a full understanding about a problem, but a new perspective opens a new opportunity. And that is great.

On the flip side it is important to listen to one another. Sometimes misunderstandings arise about what a field can do or cannot do. In collaborative projects communication is key. We all need to be open to one another. Everyone brings something to the table. We are learning to be open to challenges, surprises and opportunities.

Outside the world of sewers you are also looking at biomarkers that would predict the relapse for ulcerative colitis in patients. Tell me about that research.

Ulcerative colitis is a chronic condition. Patients can go on remission when they stop having signs of colitis, but about 30% of patients have at least one relapse per year, which is very painful and puts a big stress on their normal life.

Today we may find biomarkers in the colon if we do a colonoscopy, but that is both costly and not easy to perform regularly. We want to find a better solution, that is easily accessible and low cost. So we are carrying a study to follow patients longitudinally over a year in the hope that we will find biomarkers in their bodily fluids that would lead us to understand when a relapse is developing.

We believe there may be biomarkers that appear even a few months before a relapse. The advantage of early intervention could be that the relapse could hypothetically be averted altogether or minimized.

 What is happiness to you?

 I really enjoy the process of giving life to ideas!

What is the most underrated value?

Freedom to explore. Happiness and value can be found in many unexpected places. We should have that freedom to explore outside what is expected. 

What is the most overrated value?

 Deep specialization is often overrated. The world and the challenges we face are not divided by technical areas: they are interconnected. To address our world’s challenges we have to be comfortable collaborating with people outside our comfort zones.

Do you have a live motto?

Take risks and don’t over plan life. We change as people and the world changes so fast.

I don’t see value in over strategizing one’s life. I think we need to keep talking to people and keep our eyes open for what the world needs from us.

Photograph: MIT, Casey Atkins

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