Syntroleum Corp. says it has received unsolicited offers for the company or its assets and that it is considering the propositions. The  Tulsa, Okla.-based   company, which is engaged in a joint venture with Tyson Foods, says it has hired an investment banker to review its options.

Syntroleum and Tyson Foods together own Dynamic Fuels LLC, which has a plant in Geismar, La., that produces biodiesel from animal fats and greases. The plant started production several years ago but has been idled. Syntroleum says the plant is ready to resume production.

The Tulsa World reported that other companies are interested in intellectual property owned by Syntroleum, such as its patents.

Syntroleum reported first-quarter 2013 net income of $11 million and a $2 million net loss.