Research on using Marchantia polymorpha, commonly known as liverwort, a plant closely related to moss, for food and as an ingredient in medicine and supplements is being conducted at Kobe University. Not only can liverwort be cultivated quickly and in large amounts, it’s also very nutritious, a trait which has gathered attention as the space food of the future. As its genes can be easily manipulated in experiments, liverwort also shows great potential to be used to produce various useful substances. At the center of this research is Professor ISHIZAKI Kimitsune of the Graduate School of Science. He told us more about the hidden potential of liverwort and its future industrial applications.
Producing rare polyphenols using liverwort
Why did you start your research on liverwort?
Ishizaki:
Plants first emerged on land about 500 million years ago, and were then split into bryophytes and vascular plants — plants with a system of tubes for transporting water and nutrients. Those vascular plants then divided further into groups such as plants with seeds and flowers and ferns, spreading all around the world.
I research the evolution of plants, a field in which bryophytes are extremely important. Bryophytes contain a structure similar to the ancestor of land plants, making them quite useful for elucidating basic principles common to all land plants and for investigating the evolutionary process.
Among these bryophytes, liverwort is currently gathering worldwide attention as a model plant for various experiments. What’s special about liverwort is that it grows extremely quickly, meaning that experimental results come just as fast, making it easy to conduct experiments involving gene introduction and modification.
Back when I was at Kyoto University in the early 2000s, they were starting to make liverwort into a model plant, so I began my research as a part of that work. Thanks to researchers from all over the world participating in this research, in 2017, we elucidated the liverwort genome, solidifying its position as a model plant.
Why did you begin research on industrial use?
Ishizaki:
My research involves fundamental research at the genetic level in the field of plant molecular biology. About five years ago, I had the opportunity to speak with Professor MIZUTANI Masaharu (an expert in plant metabolic engineering) of the Graduate School of Agricultural Science, which kicked off our joint research. Professor Mizutani is my senior at Kyoto University and is known for his research on producing various materials using the power of plants.
My research group is currently working on production of polyphenol using liverwort. Polyphenol, which has been gathering attention for disease prevention through its antioxidant effects, comes in thousands of different varieties, but most of the ones used in medicine and supplements are imported from regions like China and Africa. Thus, it’s possible that polyphenols could spike in price or become depleted due to the effects of the political climate overseas.
Thus, we’re trying to rearrange cells so that we can utilize liverwort’s easily manipulatable DNA to produce rare and valuable polyphenols. Liverwort has always had a metabolic system for producing certain types of polyphenol, so we’ll modify that system to produce valuable ones.
Liverwort can be quickly cultivated in large amounts, so if we use this method, we can extract a lot of high-value polyphenol. This will allow us to manufacture as much as we need without relying on imports. Gathering attention for its potential effects in treating pollen allergies and preventing dementia, we aim extract polyphenol components from liverwort, which contains more of the substance than things like grape skins and citrus fruits.
Can liverwort be produced in space someday?
What have you focused on as far as potential as food?
Ishizaki:
During my research, I thought to myself, ‘Rather than just using liverwort to produce and extract useful substances, couldn’t we just eat it as is?’ Working together with Assistant Professor YUASA Masahiro of the Graduate School of Human Development and Environment, who performs research on unused food resources, we began investigating the potential of liverwort as food.
Wild liverwort is unsafe and not very tasty, so we don’t use it as food, but the liverwort we grew in our laboratory was like a vegetable, with a lettuce-like crunch. After having a specialized agency that analyzes food take a look at our liverwort, we found that it had no toxicity and contained lots of vitamins and minerals. In particular, we found that liverwort contains 25 times the iron of that found in spinach. Also, liverwort contains eicosapentaenoic acid (EPA), which is found in abundance in “blue-backed fish” such as sardines, herrings and mackerels.
Soil isn’t required to grow liverwort; all you need is to apply the right amount of mist. You could even set up a liverwort factory and grow it in desert areas. In the future, bringing all the food you would need from earth would be difficult on a long trip to, say, Mars, so it could be possible to grow liverwort in a space station. It grows very quickly, so being able to grow a lot of it in a small space is a plus.
You could also have liverwort produce polyphenol and just eat it as is, like an edible supplement, thus eliminating the cost of extracting the polyphenol. Liverwort also dries out very easily, so you could use that trait to turn it into a powder and use it for all sorts of applications.
I hear you’ve also been working on recipes for liverwort cuisine.
Ishizaki:
With help from Assistant Professor Yuasa, we had a cuisine specialist make us some dishes using edible liverwort. In addition to eating it uncooked in a salad, we discovered that you can use it for tempura, in simmered dishes and even in traditional Japanese sweets, and it tastes great. We also had the opportunity to make samples of cookies using dried liverwort powder, which were also quite delicious.
However, liverwort has never been used as food before, so people assume that it will taste awful. We need a way of getting people to overcome these preconceptions and try our liverwort cuisine. I think a lot of people have an aversion to the name “liverwort,” so my research group and I are thinking of a new name for it to make it more approachable as food.
Contributing to carbon neutrality
What is the outlook of your research in terms of social implementation?
Ishizaki:
We’ve got a basic patent for cultivating large amounts of liverwort, so I hope to be able to implement a cultivation system in society within the next two years or so. Once we’re able to actually produce liverwort, I plan to start up a corporate organization. We’ve already begun joint research with food manufacturers and food ingredient manufacturers that produce rare compounds found in plants.
We know that as liverwort grows, it absorbs large amounts of carbon dioxide. If we can produce useful materials while contributing to carbon neutrality, it would provide huge benefits for the industrial use of liverwort.
In the field of biomanufacturing, research is being conducted using microorganisms, but not much research is done using plants. Moving forward, however, I think the use of liverwort will greatly expand the potential of research using plants.
Resume
In 1996, graduated from the Faculty of Agriculture, Kyoto University. In 1998, received his master’s degree from the Graduate School of Agriculture, Kyoto University. After working for a pharmaceutical company, in 2003, he finished the doctoral program at the Graduate School of Agriculture, Kyoto University and received his doctoral in agriculture. After serving as a research fellow at the Japan Society for the Promotion of Science and a research associate in the Department of Plant Sciences, Oxford University, in 2006, became specially-appointed assistant professor at the Graduate School of Biostudies, Kyoto University and in 2008, assistant professor at the same graduate school. In 2013, became associate professor at the Graduate School of Science, Kobe University, and professor in 2020.
