Biomanufacturing of Dihydroxyindole for Natural Hair-Color Products


At Kao, we make use of mild and highly selective enzyme reactions and other bioprocesses to manufacture a number of proprietary ingredients, including detergent enzymes and certain cosmetic bases. A recent breakthrough in this area was the successful development of an efficient process for large-scale commercial production of dihydroxyindole (DHI), a precursor to the melanin responsible for black hair. DHI is a key ingredient in Kao’s Rerise brand hair color for gray hair, which uses 100% natural dye.

Gekkeikan, a sake manufacturer with a history going back almost four centuries, developed the original process of synthesizing DHI using tyrosinase from the Aspergillus oryzae fungus. However, it was a slow and labor-intensive process, unsuitable to mass-production of a commercial product like Rerise. Selectively and reliably producing DHI requires minutely calibrated adjustment of reaction conditions, such as oxygen concentration and pH, at each stage of the process. Originally, this was accomplished by human technicians with years of experience, who were able to predict reaction behavior and adjust conditions as needed. To make efficient use of DHI in a commercial product like Rerise, it was necessary to find a way of controlling reaction conditions at high volumes and without human intervention.In response, we utilized experimental data and simulation technology obtained on each scale to develop an automated system that has made large-scale commercial DHI production a reality.

Our innovative DHI production process was made possible by the marriage of Gekkeikan’s biotechnical expertise, the product of a long tradition of sake brewing, with the bioproduction know-how Kao has developed in the manufacture of enzyme detergents and other commercial products.

Related Actions and Goals

Kao’s ESG Strategy Kirei Lifestyle Plan


Sustainable Development Goals

SDGs GOAL 12:Responsible Consumption and Production

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