It depends on what type of bio-fuel you are looking at. If you are looking at bio-deisel, then no, your gas engine will never want to see it. If you are looking at something like alcohol, then you should be able to.
I believe you can only convert to biofuel if your car runs on diesel.
Changing a gasoline-burning vehicle to diesel would be very time-consuming and costly. You'd have to change the engine and a bunch of other parts as well.
