Shares of Cyanotech Corp. surged by the most in almost three years after the Kona-based company reported a jump in profit and historic quarterly revenue.

The company's shares yesterday rose 28 percent on the Nasdaq Market, the most on a percentage basis since Aug. 17, 2006, in gaining 55 cents to $2.50.

Cyanotech, a producer of nutritional products using microalgae technology, is one of Hawai'i's smaller publicly traded companies, but has charted the biggest gain of any of them this year. Its shares have climbed 71 percent since the start of 2009.

Andrew Jacobson, Cyanotech president and chief executive officer, downplayed the stock price gains in favor of what the company is accomplishing.

"Results and the sustainability of it is really what we're looking at here," said Jacobson, who was appointed to his post in May 2008.

To be sure, Cyanotech has had its ups and downs, with the company having to resort to a 1-for-4 reverse stock split in 2006 when its shares sank below 50 cents each. Its price remains far below the $15-a-share high on a split-adjusted basis reached in early 2000.

The stock jump yesterday followed Cyanotech reporting a 52 percent surge in net income as profit for the quarter ended June 30 jumped to $413,000, or 8 cents a share, from net income of $271,000, or 5 cents a share, a year earlier.

Jacobson said the company has worked to contain and cut costs while pumping up its productivity.

"Really what we focused on here is good, sound business practices."

At the same time, Jacobson said, the company has built up branding for its its BioAstin Natural Astaxanthin and Hawaiian Spirulina Pacifica, positioning them as premium products produced in a pristine environment.

That's helped increase sales, with revenue rising to $4.02 million in the just-ended quarter, from $3.7 million a year earlier.