The stickiness of natto hides a myriad of secrets.
The reason for natto’s peculiar stickiness is its high concentration of poly-γ-Glutamic Acid or PGA. Poly means “a lot,” PGA means “a lof glutamic acids connected.” PGA is a natural viscous substance produced by Bacillus natto during natto’s fermentation. Its peculiar properties allow a wide range of applications.
（1) Water purification
PGA can turn stagnant water into clear water. By adding PGA to dirty water, its viscosity entwines the small dirt particles and settles them into large lumps.
The dirt trapped with natto bacteria precipitates to the bottom. Eventually, the natto bacteria decompose it purifying the water. This water purification method is used in Japan and overseas.
（2) Water retention
PGA can store up to 5000 times its weight of water. Its applications include water-retaining material for desert greening and water-absorbing material in diapers.
Another popular application is as a moisturizer in skincare and hair care products.
（3) Biodegradable plastic
At a glance, biodegradable plastics are similar to ordinary plastics. However, the most significant difference is a harmless re-incorporation into nature, resulting from a fast decomposition into water and carbon dioxide by the action of microorganisms.
PGA can be used for manufacturing bio-degradable resin with a reduced negative impact on the environment.
（4) Healthy food
PGA is used as a raw material for health foods applications such as mineral absorption, promoting materials, and oral moisturizers.
The most exciting fact is that 50-80% of the PGA produced by Bacillus natto is D-glutamic acid. Two types of amino acids exist in nature, L-type, and D-type. They have a three-dimensional structure that is reversed left and right as reflected in a mirror.
L-type amino acids are common components of most living things, including humans. However, D-type amino acids are rarely present.
The unusually high production of D-type glutamic acid by Bacillus subtilis is a mystery. Research on D-type amino acids can lead to striking discoveries of the development and evolution of life. It is also a good standing point for researching the existence of extraterrestrial life forms.
Undoubtedly, natto is still full of wonders.
Sonomono Inc. Academic Advisor
Mr. Ogasawara graduated from Kumamoto University Graduate School of Medical Education. He actively researches and develops functional raw materials such as nattokinase. His professional experience as a researcher over more than 35 years includes microbiology, fermentation, enzymology, and bacterium.