A private investment firm has bought paper recycling company Manistique Papers for an undisclosed amount.

The acquisition by The Watermill Group, of Lexington, Mass., was approved by a court after an auction and confidential bidding, the company said in a news release.

The purchase adds to Watermill’s holdings of environmental paper manufacturers, which also includes FutureMark Paper Co., a leading producer of recycled coated paper. The deal gives Watermill companies in both the coated and uncoated, 100-percent recycled paper markets, the firm said in a news release.

The company now represents production of nearly 300,000 tons of printing paper made through recycling.

Manistique Papers operates a 72-acre manufacturing site at its headquarters in Manistique, Mich., that can produce up to 500 tons of recycled pulp per day and approximately 130,000 tons per year of uncoated, 100-percent recycled paper.

“We’ll use the strategies proven at FutureMark to revitalize and grow Manistique, building a stronger employer for the local community, driving new investor value by leading the high-value market for sustainable paper and creating a wider assortment of environmental paper products for our Fortune 500 customers,” said Steven Karol, Watermill founder and managing partner.

To maximize synergies between Manistique Papers and FutureMark, Watermill will run both organizations as sister companies under a joint management structure led by Steve Silver, FutureMark president and CEO. Each company will be separately owned and operated.