Although midorimushi literally means the green bug, euglena is not a kind of bug. It is a type of microalgae, just like the seaweed, which is a kind of algae too. It has existed since 500 million years ago, and it is just about 0.05mm long. It has both plant and animal characteristics – like plants, it can carry out photosynthesis; like animals, it has the ability to move on its own.
While nutrients from both plant and animal sources can be found in euglena, it does not have a hard cellulose cell wall like that of a plant cell. Therefore, its nutrients are easily digested and absorbed by humans. It has become increasingly popular as a food ingredient for good health. Presently, it is gaining attention for its potential to serve as an ecologically-friendly source of biofuel, as well as other applications.
Euglena has numerous micro pores in its sponge-like structure. It contains paramylon. With functions like dietary fibre which helps to get rid of unwanted substances from the body*, paramylon is a type of (β)-glucan that is also contained in Agaricus (mushrooms) and Lingzhi mushroom (bracket fungus). However, paramylon can only be found in euglena.
* Refers to the management of unhealthy dietary habits.