Five Questions and an Elevator Pitch: FunGuys

1. What is the need that your project seeks to address?

Franklin: Rice is the third-largest staple crop in the world, and more than 90% of annual yields are produced in Asia. Of the estimated 144 million rice farmers, most are making a low income by managing small acreage plots of land in dry, open fields. An important issue is that for every ton of rice harvested, 1.5 tons of straw residue is produced. Management of this waste product traditionally involves burning the rice fields, as this solution requires minimal labor and cost. Field burning, however, has immense negative impacts on human health, due to poor air quality that contributes to respiratory and other diseases as leading causes of mortality for farmers. It also has systemic impacts on the planet and human health linked to the significant emission of greenhouse gases, such as methane, nitrous oxide, and particulates. The burning further disturbs the soil microbiome, reducing the fertility of the land, which itself has long-term effects.

Other more economical and safe disposal solutions, such as composting or straw collection for sale or disposal, are costly, labor intensive, and not a viable option for low-income farmers who need to turn over their fields quickly. Also, rice straw doesn’t have much value beyond lining livestock stalls or filling mattresses.

2. How does your solution work?

George: We are investigating how to reduce the harmful impacts of this agricultural waste product by using fungi to cost-effectively convert rice straw into a useful byproduct that has economic value.

Franklin: Previous research shows that fungi are good at breaking down the fibrous lignocellulosic structure of rice straw. We were interested in finding a way to genetically engineer a fungus that could quickly and easily degrade rice straw and turn it into a valuable product—whether that's a source of nutrition or a commodity product that farmers can sell to generate an economic return. We connected with a postdoctoral researcher at University of California, Berkeley, Vayu Hill-Maini, who has been developing genetic tools for transforming the common aspergillus fungus. He provided us with the synthetic biology toolkit for the genetic modification of this fungus. George and I began investigating how we could engineer the fungus to start expressing an enzyme, called xylanase, that could turn the rice straw into a valuable commodity product in an eco-friendly and cost-effective way. Our hope is that this approach will benefit farmers economically while improving human and planetary health as an alternative to field burning.

George: Xylanase is commonly used in a myriad of industrial applications; for instance, in the manufacturing of paper, food, animal feed, biofuel, and textiles. Our idea is that the fungus, which already has been determined to grow fairly well in the low-nutrient environment of rice straw, would digest the straw and convert it into xylanase. The xylanase could then be extracted and purified using a solid-state fermenter, that uses very little water, and turned into a saleable commodity. The use of fermenters for enzyme production in the fermentation and food processing industries is not a new concept, but our solution represents a novel approach.

3. What motivated you to take on the project? And what activities have you undertaken?

George: Fungi are under-studied and under-characterized, but they are a powerful tool in synthetic biology. I’m interested in expanding our knowledge about the practical uses of extraordinarily resilient organisms like fungi and applying that information to the advancement of human and planetary health. I feel that the discovery and development of new basic science and biological tools in this area also will open doors for the development of additional sustainable applications.

Franklin: This project is exciting because there can be some compelling planetary health benefits if we address greenhouse gas emissions. Solving the issues with rice straw burning also can help move us toward more circular farming practices, where waste products from producing staple crops are used to create products of value. This is attractive because human and planetary health are closely intertwined. We could have a profound impact on the lifespans of people who might otherwise die prematurely if current practices continue.

In terms of our progress, George and I are pursuing the project as independent research through Biodesign NEXT now that the Senior Bioengineering Capstone course has ended. Our current efforts are focused on fully transforming the aspergillus fungus with the construct that we've made and the toolkit that Vayu provided, as well as purifying our xylanase enzyme successfully. What we're trying to prove is that we can produce meaningful amounts of enzyme yield that could be scaled up through an industrial process.

4. What are the most important things you learned in advancing your project?

Franklin: It’s been exciting to dip our toes into this new realm of bioengineering.

George: The natural world has provided us with such a great diversity of organisms that we haven’t yet characterized well. This project has shown us that there’s still a great deal that we can learn and study that could have great potential for the advancement of life sciences and human health.

5. What advice do you have for other aspiring health technology innovators?

Franklin: You don't have to look at the need you’re trying to address through the framework of an individual patient. You can look at more of a systemic level, as well. When taken in sum—for example, changing agricultural practices to potentially benefit millions of small farmers—you can have a profound impact on human health.

I would also say to look for need areas that are not on the beaten path.

George: Don’t be afraid to shy away from the well-accepted standard bioengineering tools. We have the techniques and knowledge to build our own tools, so use these to develop new model organisms and innovative solutions.