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Kashiwanoha Soft Cellulose Utilization Project

In 2009, the Japanese government granted funding for a 3-year project that examined the viability of producing bio-ethanol from “soft cellulose” such as rice straws. The funding was granted to 4 regions in Japan: Hokkaido, Hyogo, and Akita prefectures, as well as at Kashiwanoha in Chiba prefecture. Each region is developing their own strategy and technology for the project.

How is bio-ethanol made from rice straws at “Kashiwanoha”?


Mashing & Washing

Masher Cleaned and compressed material
The rice straws are ground into small pieces using a masher. Blades within the masher rotate and break down the material, which is cleaned and compressed. Water is injected in the process to wash away dirt and sand.

Alkaline Treatment & Pulp Washing

Removing digested biomass Washed pulp being dried
Ground rice straw, water, sodium carbonate and sodium sulphite are placed in a globe digester and heated with steam to cook. The contents are then allowed to cool slowly before the pressure in the digester is released. The lid of the digester is opened and the cooked pulp is removed. The black liquor that contains lignin is drained from the pulp. The cooked pulp is cleaned with water to remove any remaining lignin and chemical residues. The pulp is then spun to remove excess water.

Enzymatic Saccharification

Top of the saccharification tank Sugar solution in the tank after 24 hours
The ground pulp is diluted in a tank with water and heated with steam to kill any microbes that may hinder the saccharification process. The temperature is then lowered to 50°C, the pH adjusted to 5.0, and the enzymes are added to start the saccharification process.


Sugar solution undergoing fermentation Adding yeast
Yeast is added to the sugar solution and left to ferment for 24 hours to produce ethanol.


The fermented solution is distilled to produce 96% pure ethanol. The total process takes 7 days from raw material to final product.
Raw Ingredient: Rice Straw    Finished Product: Ethanol