The productivity and innovation of U.S. agriculture is driving a transformation to bio-based products across the economy that is supporting millions of jobs and significantly displacing fossil fuels, according to a study from the U.S. Department of Agriculture on Wednesday.

"We need to think more broadly, beyond fuel and energy, that there is an amazing opportunity in chemicals, in enzymes, in bio-plastic materials, in forest products," USDA Secretary Tom Vilsack said in an interview.

"It's the kind of opportunity that can truly revolutionize and change the American economy so it becomes much more balanced," Vilsack said.

The report, An Economic Impact Analysis of the U.S. Biobased Products Industry, was commissioned by USDA under the 2014 federal farm bill and produced by a team led by specialists at Duke and North Carolina State universities. It examines the "bio-economy," or processes based on using renewable plant and animal resources to produce food, fuels and other materials.

The most visible aspect of the bio-economy is bio-fuel such as corn-based ethanol that has expanded rapidly with government support in the past decade.

But the report largely excludes energy, food, livestock and pharmaceuticals to illustrate less well-known sectors such as bio-plastics, bio-based chemicals, forestry and textiles.

"The total contribution of the bio-based products industry to the U.S. economy in 2013 was $369 billion and employment of four million workers," the report says.

The report includes case studies from companies including Ford, John Deere, Penford, Novozymes, Coca-Cola , DuPont and Patagonia.

USDA says it has about 20,000 bio-based products in its "BioPreferred" database and that number is growing almost daily.

"In terms of the dollar value of products sold, direct sales of bio-based products in 2013 were estimated to be nearly $126 billion," the study said, which "generated another $126 billion in indirect sales and $117 billion in induced sales."

Bio-based materials are displacing petroleum in chemical feed stocks as well as in materials, such as the use of natural fibers as packing and insulation instead of synthetics such as Styrofoam.

"We estimate that the use of bio-based products is currently displacing about 300 million gallons of petroleum per year. This is equivalent to taking 200,000 cars off the road," the report said.

The study recommends USDA's backing for bio-based product production credits and a "USDA Certified Biobased Product" label among other steps to expand the bio-economy.