Mascoma, a cellulosic ethanol maker, has been working on gaining capital investment from just about every funding source out there. But now it looks like the attempts to go public and raise $100 million have been pulled off the market.

Gigaom's Katie Fehrenbacher had been puzzled that a company with weak financials – including 86 percent of its revenue coming from government grants – filed to launch an initial public offering. That happened about a year and a half ago but the effort never made it to the stock market.

The other 14 percent of Mascoma's revenue came from selling its next-generation yeast to corn ethanol makers to cut their costs. Mascoma has wanted to go in a different direction – producing next-generation cellulosic ethanol from plant waste and not corn, with the waste coming from wood waste in a Michigan factory.

The company said it was "market conditions" that made it withdraw the public offering.

The Mascoma stock market launch was waiting in the wings until this month, when the company quietly withdrew its IPO plan. The company said it was "market conditions" that made it withdraw the public offering, even though, as Fehrenbacher writes, macro IPO conditions seem a little bit better this year than in 2012.

Another confusing pre-IPO action was Mascoma raising a few million dollars in debt during two rounds over the past six months. That didn't make a lot of sense for a company preparing to go public. Government grants have taken a bigger slice of the pie since the initial filing a year and a half ago. Its latest revenue numbers, from a year ago, said that government grants and awards made 93 percent of its revenue – up seven percent since its initial filing six months earlier.

Mascoma was founded in 2005 by Dartmouth professor Lee Rybeck Lynd. Since that time, company management has secured government funds and at least over $100 million from private capital firms and corporations including Khosla Ventures, SunOpta, GM and Marathon Oil (General Motors took an equity stake in Mascoma in 2008). The US Department of Energy awarded it $80 million, though its not clear if all the funds came through. The state of Michigan offered the company a $20-million grant to build its factory in Michigan.

Advanced biofuels has been a very tough business to break into, and other companies have failed in taking cellulosic ethanol to scale.