A US airline has completed the first test flight of a plane partly powered by biofuel derived from algae. The 90-minute flight by a Continental Boeing 737-800 went better than expected, a spokesperson said.

One of its engines was powered by a 50-50 blend of biofuel and normal aircraft fuel. Wednesday's test is the latest in a series of demonstration flights by the aviation industry, which hopes to be using biofuels within five years.

The flight was the first by a US carrier to use an alternative fuel source, and the first in the world to use a twin-engine commercial aircraft (rather than a four-engine plane) to test a biofuel blend. The flight from Houston's Bush Intercontinental Airport completed a circuit over the Gulf of Mexico, and pilots carried out a series of tests at 38,000ft (11.6km), including a mid-flight engine shutdown.

"The airplane performed perfectly," test pilot Rich Jankowski told the Houston Chronicle newspaper. "There were no problems. It was textbook."