AMES, Iowa — Renewable Energy Group Inc. announced Tuesday that it has closed its acquisition of the assets of Syntroleum Corp.

Syntroleum advised REG earlier Tuesday that a majority of its shareholders had voted to approve the asset sale to REG. Shortly after officials from the two companies completed the transaction.

Most of the employees at Syntroleum’s Tulsa headquarters will join REG.

“We are very pleased to bring new advanced biofuel technologies into the REG portfolio of products that will expand our biomass-based diesel business and launch us into new customer segments,” said Daniel J. Oh, Renewable Energy Group Inc. president and chief executive officer. “We welcome the newest members of our team in Tulsa to REG Synthetic Fuels.”

Syntroleum pioneered renewable diesel fuel and Fischer-Tropsch gas-to-liquids technologies and built a large IP portfolio, including 186 patents issued or pending, which REG will now own. Headquartered in Ames, Iowa, REG owns and operates nine active biorefineries in five states and distributes biodiesel through a national network of distribution terminals.