Dr. Walter De Logi, co-founder and chairman of Ceres Inc., has died unexpectedly, the company announced Tuesday. He was 63.

De Logi served on the board for the Thousand Oaks agricultural biotech since the company's inception and as chairman since 2002. He was Ceres' president and chief executive from 1996 until 2002.

The death comes as the company has struggled to find a market for its genetically engineered sweet sorghum seeds for ethanol production. It has not announced a profit since going public in 2012 and has had trouble penetrating its targeted market in Brazil.

Ceres was founded in 1996 by a group of investors including De Logi. He had worked in alternative energy for decades, serving as chief executive of Plant Genetic Systems from 1986 to 1996, a plant biotechnology company that was eventually sold to a German conglomerate Bayer AG subsidiary. He held an MBA from Harvard University and a PhD from the California Institute of Technology.

The company declined to state the cause of death or exact date, citing family privacy issues.

“We are deeply saddened by the loss of our dear friend and colleague, and our thoughts are with his family during this difficult time,” said Ceres Chief Executive Richard Hamilton, in a statement. “Walter was a remarkable individual – a mentor to many and a visionary who believed deeply in the positive impact that plant science could have on the world. He leaves us with a tremendous legacy and will be deeply missed.”

Shares closed down a penny to 64 cents on the Nasdaq.