Fungi use long networks of filamentous threads to absorb their food called mycelia, as a network of threads they lack the ability to digest food internally so they produce a huge range of compounds which it uses to break down living and dead material. These compounds and the resilient nature of fungi mean that they are ideally suited for use in bioremediation cleaning up chemicals and other damage that humans have wrought on the environment. Naturally fungi break up wood and other plant material into simple molecules easily used by other organisms thus building up the soil layer and speeding the recycling of nutrients through the ecosystem.
A particularly stunning example of the possible uses for mushrooms is illustrated by the use of oyster mushrooms to break up oil. As part of a competitive trial 5 piles of soil were soil were soaked in oil and then different remediation techniques were used including bacterial, chemical and fungal to attempt to get rid of the oil. Four weeks later when the covers were pulled off the fungal trial it was covered in large healthy oyster mushrooms. The mushrooms had broken the carbon chains in the oil and had gassed off the carbon as carbon dioxide ridding the soil of 95% of the oil in it. The mushrooms were also safe to eat. As the mushrooms rotted away after 8 weeks flies were attracted - these ate the remanants and spread the mushrooms spores. The flys presence attracted insects which brought in birds which then brought in seeds creating an oasis of life.
Similar processes to those above allow fungi to destroy other carbon based chemicals including pesticides such as roundup and ddt. As fungi have evolved to break down materials in their surroundings and can produce a raft of useful compounds for this purpose they are uniquely placed to help heal our scarred landscapes. I havnt found much reference to using fungi in books but paul stamets website and books are probably a good place to start http://www.fungi.com/mycotech/mycova.html
Myco filtration is the purposeful straining of water through fungal mats to rid the water of pollutants or harmful bacteria. Paul stamets a key researcher in fungi has proven that mushroom beds can be used effectively to filter and rid water of E. coli. Another fungi has been proven to completely inhibit the parasite that causes malaria.
The intelligence of fungi should not be underestimated as a team of japanese researchers who put a slime mould into a maze found out
A group of Japanese researchers recently demonstrated the existence of what they
called "cellular intelligence." They put a slime mold into a maze and gave
it two food sources. The slime mold split itself and chose the shortest distance
possible, navigating throughout the maze as directly as possible to
both food sources.
This is perhaps not as suprising as it may seem as fungal mats have a similar layout to the brain or perhaps the internet and fungi are hundreds of millions of years old. Life without fungi would be impossible underestimating their potential in a post carbon (pun intended) world would be a mistake.
Much info gained from http://foodandfarming.bioneers.org/node/14