Struggling biodiesel company Imperium Renewables Inc. said existing investors have recapitalized the business to help settle some of its debts.

The Seattle-based company did not specify how much money or which investors took part. It was also unclear if the investment changed the makeup of the board.

The majority of the proceeds went to satisfy debts to French bank Société Générale, lien holders and unsecured creditors, Imperium said in a statement.

The company said it had retained an “independent third party business debt restructuring firm” to help negotiate with its creditors to settle its remaining debts and retain enough capital to resume operations. Imperium will continue to focus on biodiesel production at its Grays Harbor refinery, a 100-million-gallon facility that opened in summer 2007.

“This funding is a significant step in the process we set forth in January to turn this company around, but we still face hurdles as the amount of funding is limited,” said John Plaza, the company’s founder and CEO, in a statement. “Despite the recent and overdue correction in the commodities markets, the biodiesel industry remains extremely volatile and the company is still under stress.” He went on: “We will continue to make deliberate operating decisions intended to ensure the long-term viability of the company. We have not lost sight of our original mission of producing environmentally sustainable alternatives to petroleum fuel.”

The company declined to comment beyond the statement. Imperium has encountered a litany of problems over the past year, including the departure of CEO Martin Tobias, the cancellation of a $345 million initial public offering and numerous layoffs.

Earlier this year, the company lost a key contract for its Grays Harbor refinery to supply biodiesel to Royal Caribbean Cruises. The company’s troubles come amid growing concerns over the economic viability of biodiesel.

Many early forms of biodiesel used feedstocks that compete with food crops for agricultural land. Imperium was one of the most heavily funded startup companies in the state, raising $214 million from investors last year. Past investors in the company included Nth Power, Technology Partners, Stark Biodiesel Investments and Capricorn Management. None of those investors returned calls.