How do fungi acquire their nutrients

A few fungi attack small living organisms so aggressively that they have been called carnivorous. Many fungi defy easy categorization, acting as saprotrophs, symbionts, or carnivores at various stages of their life cycles , or in interactions with different organisms. Necrotrophic fungi act both as symbionts and saprotrophs. These fungi infect a living host, which they kill over time, then continue to consume of the dead tissues of the host.

Continue on to Symbiotic Fungi Quick links to Content. I ntroduction to Fungal Biology. Wherever the fungi is, they simply absorb everything around them that they can. Instead of reaching for the yogurt, a fungi spore would end up in the yogurt cup randomly, and just absorb all the nutrients from the yogurt passively.

Fungi cells have an extremely efficient surface area to volume ratio , which means that each cell has a ton of surface area with which to absorb nutrients. Once they absorb it through a process not unlike endocytosis, they break down most of the nutrients they absorb using various enzymes. Hydrolytic enzymes break down polysaccharides, proteins , and lipids , cellulase breaks down cellulose.

The part that gets complex is that there are millions of types of fungi. Some are parasites and leech nutrients off of their hosts, others are symbionts that help provide nutrients to their hosts for example, some fungi actually live in the roots of a plant and help break down nutrients for the plant to absorb , and others are decomposers like mushrooms. Each one has a slightly different method of absorbing nutrients and a different source, but the basic enzymes and processes are the same.

How do fungi absorb nutrients? Many types live in symbiosis with animals, as the fungus and animal rely on each other for essential services. Cows and other animals that eat grass depend on gut fungi and other microorganisms to help break down lignin, cellulose, and other materials in wood's cell walls.

While fungi only make up 8 percent of the gut microbes, they break down 50 percent of the biomass. To figure out which enzymes the gut fungi produce, Michelle O'Malley and her team at the University of California, Santa Barbara grew several species of gut fungi on lignocellulose.

They then fed them simple sugars. As the fungi "ate" the simple sugars, they stopped the hard work of breaking down the cell walls, like opting for take-out rather than cooking at home. Depending on the food source, fungi "turned off" certain genes and shifted which enzymes they were producing.

Scientists found that these fungi produced hundreds more enzymes than fungi used in industry can. They also discovered that the enzymes worked together to be even more effective than industrial processes currently are. O'Malley's recent research shows that industry may be able to produce biofuels even more effectively by connecting groups of enzymes like those produced by gut fungi.

Some fungi work outside the guts of animals, like those that partner with termites. Tropical termites are far more effective at breaking down wood than animals that eat grass or leaves, both of which are far easier to digest.

Young termites first mix fungal spores with the wood in their own stomachs, then poop it out in a protected chamber. After 45 days of fungal decomposition, older termites eat this mix. By the end, the wood is almost completely digested. Scientists assumed that the majority of the decomposition occurred outside of the gut, discounting the work of the younger termites.

But Hongjie Li, a biologist at the University of Wisconsin, Madison, wondered if younger insects deserved more credit. He found that young workers' guts break down much of the lignin. In addition, the fungi involved don't use any of the typical enzymes white or brown rot fungi produce. Because the fungi and gut microbiota associated with termites have evolved more recently, this discovery may open the door to new innovations.

From the forest floor to termite mounds, fungal decomposition could provide new tools for biofuels production. One route is for industry to directly produce the fungal and associated microbiota's enzymes and other chemicals.

When they analyzed termite-fungi systems, scientists found hundreds of unique enzymes. A more promising route may be for companies to transfer the genes that code for these enzymes into organisms they can already cultivate, like yeast or E. An even more radical but potentially fruitful route is for industry to mimic natural fungal communities. For millions of years, fungi have toiled as short-order cooks to break down wood and other plants.

With a new understanding of their abilities, scientists are helping us comprehend how essential they are to Earth's past and future. The Office of Science is the single largest supporter of basic energy research in the physical sciences in the United States and is working to address some of the most pressing challenges of our time.

Anaerobic gut fungi colonize plant matter and release enzymes that break cell walls into simple sugars. Photo courtesy of Carla Wick. The evolution of white rot fungi most likely played a large role in trees beginning to decay about million years ago. The fungus Schizophyllum commune is one modern example of a white rot fungus.