Iowa's biodiesel plants operated at 54 percent capacity in the first quarter, producing 42.7 million gallons, the Iowa Renewable Fuels Association reported.

By comparison, biodiesel production in the state was at 41.9 million gallons in the first quarter of 2012.

The association, which is seeking legislation to create a B10 price differential to boost sales, said in a press release that the industry has seen "a strong move" toward B5 blends. There are currently 12 biodiesel plants in the state, nine of which reported production.

Iowa's biodiesel plants set a new record in 2012 by producing 184 million gallons of biodiesel, up from the previous record of 169 million gallons in 2011.