DES MOINES — South Dakota-based ethanol company POET said Tuesday it has purchased the biofuels assets of Flint Hills Resources, including five ethanol plants in Iowa and one in Nebraska. The deal also includes ethanol distribution terminals in Texas and Georgia.

The purchase will allow POET, based in Sioux Falls, S.D., to increase its production to 33 biofuels production plants in eight states. It will have a capacity to produce 3 billion gallons annually.

“This acquisition will increase POET’s ability to bring even more high-quality, plant-based biofuels and bioproducts to the world — allowing us to have an even bigger impact on fighting climate change and cleaning our air,” said POET founder and CEO Jeff Broin.

The Iowa ethanol plants are in Arthur, Fairbank, Iowa Falls, Menlo and Shell Rock. The Nebraska plant is in Fremont, and the ethanol terminals are in Buda, Texas, and Camilla, Ga.

Wichita, Kan.-based Flint Hills is a subsidiary of Koch Industries, and the transaction includes the subsidiary’s entire biofuels portfolio. Flint Hills also has oil refineries and makes other products, including chemicals and asphalt.

POET also makes other products including distillers dried grains, a high protein animal feed and corn oil.

Details of the transaction were not released.

Ethanol plants struggled and many closed during the height of the coronavirus pandemic as fewer people drove cars, sending the sale of gasoline and the ethanol additive plummeting. Sales have since improved and production has increased.