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Utah State University
Jixun Zhan, Utah State university associate professor of biological engineering has secured a patent for the production of a natural blue dye known as indigoidine.

LOGAN — A Utah State University researcher has taken a big step toward making a safer, more natural dye that can be used in the food, textile, cosmetic and other industries.

Jixun Zhan, an associate professor of biological engineering at USU, has secured a patent for a method to produce the deep blue dye known as indigoidine. The tint was originally synthesized from a bacterial strain found in Rhode Island and offered a promising alternative to the synthetic dyes used to color jeans, leather, food, beverages and paper.

The bacterium itself, however, does not produce significant quantities of indigoidine, so Zhan proposed mimicking the organism’s biosynthetic machinery inside a heterologous host cell: E. coli. These mostly harmless bacteria can churn out significantly higher yields of the blue pigment and provide an efficient way to produce the dye without using synthetic compounds that could pose a threat to human health and the environment.

“In the original producing strain, there is only one copy of the biosynthetic gene that synthesizes the pigment,” Zhan said in a statement. “But in E. coli, we can make multiple copies of the gene and induce its expression under a stronger promoter.”

Zhan’s patent also includes the development of a new method to further process and purify the pigment before it’s ready for use — an important step when using the colorant in food and drinks. Business experts say the patent presents an exciting opportunity across several industries.

“The demand for natural dyes is growing rapidly,” Christian Iverson, business development director for USU, said in a statement. “I’ve had a number of conversations with food- and consumer-product companies that are looking for natural dyes to replace some or all the synthetic chemical-based dyes currently in use — in particular blue.”