I think you mean 'mycoprotein'. It's easily confused with 'micro' meaning small, but in fact 'myco' comes from the Greek word for fungus. Mycoprotein is created by growing fungus, mainly one called fusarium venenatum. This grows naturally but for food is cultivated in big vats or containers. This started around 1960 when big companies like ICI were looking for cheap, alternative ways to feed the growing world population.
In Europe and the US we know mycoprotein mainly in the form of Quorn, which is the basis for a lot of vegetarian dishes. This is made by a complicated process, resulting in a high protein substance that can be used as a substitute for meat or sometimes as a replacement for dairy products. It is also a source of dietary fibre. Because egg white is used in the manufacturing process quorn has not usually been eaten by vegans, but it's hoped that an egg-free version may be possible.
There has been some disagreement about how healthy it is - you can see some of the arguments here.