Riverence, the largest trout producer in the United States, signed a joint venture Wednesday with biorefining company Green Plains to produce feed using fishmeal alternatives, namely fermented protein.

The venture will produce trout and salmon feeds for the Riverence Group, using a new fermented protein product recently unveiled by Green Plains.

As part of the joint venture, Green Plains contributed capital and supplied key ingredient services, while the Riverence Group contributed existing assets and a feed purchase agreement to support its own production.