Kailua, Kona-based Cyanotech Corp. said the company's founder, Gerald Cysewski, 58, will step down from his positions as chairman, president and chief executive officer to become chief scientific officer.

The move is part of a strategic shift in the company's business model from wholesale to retail sales of microalgae products such as natural Astaxanthin and spirulina. The change is not expected to affect employment.

The board of directors has retained the executive search firm of Heidrick & Struggles to manage the search for the new chief executive officer.

"Although the precise plan for moving Cyanotech to the marketing-driven model awaits the input of Dr. Cysewski's successor, we are intent on moving in this new direction," said Gregg Robertson, lead independent director for Cyanotech.

Shares of Cyanotech fell 4 cents, or 3 percent, to $1.21 yesterday on the Nasdaq stock market. Shares of Cyanotech are down from a split-adjusted $8 in 2003.

Cysewski is credited with commercializing the large-scale production of microalgae. He began investigating the process four decades ago while an assistant professor at the University of California at Santa Barbara.

He began small-scale operations while working with the Battelle Institute in Pasco, Wash., before choosing Kona to begin large-scale cultivation and processing of microalgae.

"I look forward to getting back into the lab full-time to pursue my goal of enhancing yields and discovering and commercializing new microalgae products for our portfolio that will provide important health benefits to our customers," Cysewski said.