A Durham-based agriculture biotech company has raised an additional $6.5 million in a private equity offering, according to a Form D filed Wednesday with the Securities and Exchange Commission.

Benson Hill Biosystems Inc. had earlier raised $18.5 million in March. The current private equity raise came from 16 investors.

Benson Hill Biosystems is a plant genomics company. It uses technologies and biological expertise to help organizations advance products to market faster and to tackle challenges in crop development.

Matthew Crisp is the president and chief executive officer of the company. Prior to co-founding Benson Hill Biosystems, he was the president of the agricultural biotechnology division and senior vice president at Intrexon Corp., a synthetic biology company.

In addition to launching the company’s ag biotech efforts, Crisp worked with Intrexon for more than five years, serving in multiple executive roles and on its board of directors. Prior to joining Intrexon in early 2011, Crisp was a managing director at Third Security LLC, a venture capital firm.

Benson Hill Biosystems is named after Andrew Benson and Robin Hill, two well-known photosynthesis researchers.

Companies relying on a Reg D exemption do not have to register their offering of securities with the SEC, but they must first file what’s known as a Form D electronically with the SEC after they first sell their securities.

Note: This story is from the North Carolina Business News Wire, a service of UNC-Chapel Hill’s School of Media and Journalism