OLD TOWN, Maine: From the outside, the rustic red-brick mill on a bend in Maine's Penobscot River resembles any other struggling American pulp and paper mill.

But along with its usual business of pulp-making, the century-old mill is doing something unprecedented: Developing technology to produce bio-butanol, a jet fuel, from parts of trees that would otherwise go to waste, one of the world's first to do so.

Production is still two years away, but the reinvention of Maine's Old Town Fuel & Fiber mill is already drawing interest as a potential model for a new wave of biofuel companies that could slash dependence on oil, create jobs and reduce the emissions that lead to global warming.