Shares of Gevo, which makes fuels and chemicals from plant matter, plunged Tuesday after the company announced it was suspending plans to produce isobutanol from corn and would instead make ethanol.

Isobutanol is an important industrial chemical that can be used as an additive to gasoline, plastics and paints.

Gevo Inc., based in Englewood, Colo., had hoped its new plant in Luverne, Minn., would be producing 1 million gallons of isobutanol per month by the end of the year.

After the markets closed Monday, the company announced that it has not made enough progress toward profitable operation at high rates. The company said it will switch to making ethanol, a well-known process, while it adjusts its isobutanol technique.

The switch from isobutanol to ethanol dims the prospect for future profits for the company, analysts said.

Gevo shares plunged 92 cents, or 27.8 percent, to $2.39 per share in midday trading after falling as low as $2.15 earlier in the session. That is an all-time low for the stock price, according to FactSet.

"This news is obviously unwelcome," wrote Pavel Molchanov, an analyst at Raymond James in a research report.

Molchanov wrote also, though, that the move to earn a profit making ethanol while trying to fix the isobutanol process is preferable to losing money making isobutanol at low rates.

Biofuels companies in general have had difficulty taking processes that look promising in laboratory or pilot-scale settings and turning them into large commercial operations that produce profitable volumes of chemicals and fuels other than ethanol. Humans have been brewing ethanol — also known as alcohol — for centuries. It comprises about 10 percent of the gasoline consumed by U.S. drivers.

Molchanov said Gevo's move was "just the latest example of the industry's frustrating but inevitable growing pains."

Gevo's process uses yeasts to turn the sugars in corn or other plant matter into isobutanol and a device that then separates the isobutanol.

Gevo's CEO Patrick Gruber said Monday he expect the company to reach its isobutanol target sometime next year.