Last week in Part I of this series, I discussed some of the unique properties of fungi – yeasts, molds, and mushrooms. This week, I’ll explain why you will be hearing more and more about fungi in the future, particularly in the areas of agriculture and environmental remediation.
Fungi play several critical roles in food production, the most fundamental being improving soil productivity. Fungi break down organic matter into compost. They extract minerals from rocks in the soil which are critical to plant growth. They also convert nitrogen from the air into nitrates which plants need as fertilizer. Recent studies have shown that inoculating soils with the appropriate mix of fungi can have as strong an impact on crop productivity as the application of industrial fertilizers. Furthermore, the effects from adding the fungi to soil are long-lasting, as opposed to fertilizers which dissipate after just a single growing season. We will know when the use of fungi in soil productivity has hit the big time when you see large agro-chemical companies like Monsanto and Cargill getting involved.
Fungi are also becoming an important food source. Global sales of mushrooms for human consumption grew by a factor of 150 from 1980 to 2005. This dramatic increase is easy to understand when you consider that mushrooms are quite the superfood. Mushrooms are not only high in proteins, but the proteins in them contain all of the 21 amino acids that humans need for a healthy diet. They are an excellent source of important minerals, particularly potassium and selenium. They are also rich in vitamins and contain high levels of folic acid and vitamin B-12 which are difficult to obtain in vegetarian diets other than by eating mushrooms. (Note to self, “Go buy some mushrooms.”)
As you can observe in your backyard after a rainy night, mushrooms grow very rapidly and they grow most anywhere. Projections on how we will manage to feed eight to nine billion people in the 21st century nearly always foresee increased mushroom production. As I researched this column, it was interesting to note that much of the current research on improved mushroom farming is occurring in India, a country already confronting food scarcity.
Mushrooms are also going to be increasingly employed in environmental remediation during the coming century. Over the years, I have read about many efforts to use bacteria to clean up soil or oil spills, but only a small number about the potential use of fungi. I am not really sure why. Mushrooms are able to metabolize (break down) a far wider range of chemical structures than bacteria. This allows them to clean up industrial wastes such as polychlorinated biphenyls (PCBs) and other complex chemicals than bacteria just can’t “stomach”. Recent studies have also shown that mushrooms and other fungi are able to break down nerve gases such as VX and Sarin and can remove residual pharmaceuticals from city waste water.
I tend to be more matter-of-fact than mystical in my writing about environmental issues. However, as I wrote this column it was hard not to consider James Lovelock’s famous Gaia Principle which “proposes that organisms interact with their inorganic surroundings on Earth to form a self-regulating, complex system that contributes to maintaining the conditions for life on the planet.” The Gaia Principle seems to be a good lens through which to view the role of fungi in our world. As human activities such as industrial agriculture, urbanization and wetlands destruction have reduced the population and diversity of fungi, our soils have become less productive, our water has become more polluted, and our collective health has declined. If we can start to take better care of our fungi, it will start to take better care of us. OK, that is about as mystical as I can manage.
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(1) Rising concentrations of active pharmaceutical agents in our water supply is worthy of its own column, if not a series of columns. They enter our waterways when people dump unused pills in the toilet (which you should never, never do – Orange County schedules collection days for these) and also through the presence of unmetabolized drugs in urine.http://chapelboro.com/columns/common-science/fungi-of-the-future
I previously published a column called “Your Mother the Plant” in which I discussed the nearly identical structures of chlorophyll, which absorbs carbon dioxide for plants, and hemoglobin, which absorbs oxygen for animals like humans. This striking similarity is an echo of the time long, long ago before the evolutionary divergence of plants and animals. Hence the reference to plants being the mother of humanity. Following this same line of reason, as I discuss below, if your mother is a plant then your sister is a mushroom.
Fungi, which include yeasts, molds, and mushrooms, are everywhere. It’s estimated that there are approximately 1.5 millions species of fungi on earth and they live almost everywhere, including extreme environments such as the Arctic, undersea vents, and deserts. If you follow the evolutionary tree of life, plants broke off from the stem prior to the division between animals and fungi. As a result, fungi and animals share a number of key traits. Fungi breathe in oxygen and exhale carbon dioxide. They get their energy by consuming food rather than through photosynthesis. Furthermore, just like humans, they are susceptible to infection by bacteria and viruses.
Fungi migrated from the oceans to the land approximately a billion years ago. Since then they have been busily producing our soil by decomposing organic material and dissolving rocks. The dissolution of rocks by fungi transforms minerals such as iron and calcium into compounds which can be absorbed by plants and animals. The iron we get from eating broccoli has been made available to us by fungi in the soil. In addition, fungi living on the roots of plants are responsible for converting nitrogen from the air into compounds which can be used by plants as fertilizer.
Since fungi can be infected by viruses and bacteria just like we can, they also produce chemicals to ward off these germs. The most famous of these chemical compounds, penicillin, was discovered in 1928 by Alexander Fleming in a contaminated Petri dish which was not washed while he was on vacation. Other molecules produced by fungi can be either poisonous or psychotropic to humans.
Humans have long utilized fungi as foods. Yeasts are used to make beer, wine, cheese, soy sauce and other fermented products. Mushrooms, at least most of them, can be eaten and provide unique health benefits.
I hope that this discussion of the similarity of between mushrooms and people and the unique properties of fungi will have sufficiently whet your appetite such that you come back for Part II next week, when I discuss the fungi of the future.
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