Biodiesel refers to a vegetable oil or animal fat based diesel fuel consisting of long chains of alkyl esters. Biodiesel is typically made by chemically reacting lipids, for example, vegetable oil, animal fat (tallow), with an alcohol. Biodiesel is meant to be used in standard diesel engines that run on regular high grade diesel fuel. Biodiesel is thus distinct from the vegetable and waste oils used to fuel converted diesel engines. Biodiesel can be used alone or blended with petrodiesel, which is regular high grade diesel fuel. Biodiesel can also be used as a low carbon alternative to heating oil. So the answer to your question is yes, biodiesel can really fuel a diesel engine.
Actually, most every engine manufacturer in the world uses biodiesel in their engines. Its a good proof that biodiesel won’t ruin your engine.