Cleantech investor SJF Ventures has added another $20 million to its third fund.

The Durham-based green venture capital firm has raised a total of $48.8 million for the fund, according to securities filings. A year ago the fund stood at $28.8 million, filings show.

Since launching in 1999, SJF has invested in “sustainable businesses,” which includes technologies in solar energy, energy efficiency, supply chain efficiency, food safety and smart infrastructure. The firm works with entrepreneurs who use new technologies and business models “to win market share from incumbent, inefficient and carbon-intensive competitors,” the company says on its website.

Last year SJF joined with Citi Community Capital, the community development lending and investment group of Citi to launch SJF’s third fund, which was expected to reach $75 million. Filings show that 83 investors have pumped money into the fund so far. SJF intends to use the fund to make equity investments in growth-stage cleantech companies.

SJF has more than $100 million under management. Money from the firm’s first two funds has been invested in more than 30 portfolio companies. Southeast investments include Troy, N.C.-based Aseptia, a sustainable food processing company; and B.B. Hobbs, a Darlington, S.C. company that develops irrigation, fertigation and on-site waste water systems.