PhaBuilder brews better bioplastics with extremophile bacteria

Guoqiang Chen has spent most of his 4-decade scientific career training microbes to make plastic. And he sees PhaBuilder, which he cofounded in 2021 with two of his former students, Yuxuan Lan and Fuqing Wu, as the culmination of all that work.

The company’s name evokes both the polyhydroxyalkanoates (PHAs) that it produces and the success Chen hopes to achieve—“Pha” is pronounced like the Mandarin word fa, which can mean “fortune” or “wealth.”

PHAs are produced by fermentation of plant-derived substances such as starch or canola oil. Depending on the microbes and the materials they’re fed, PHAs can be concocted with properties resembling those of polyolefins and other fossil fuel–based plastics. And unlike polylactic acid (PLA), the largest-volume plant-based plastic today, PHAs are fully compostable without a special facility.

But despite PHAs’ many appealing qualities, companies that make them have long struggled to reduce costs and increase production capacity to the point where PHAs can compete with other plastics. Chen has experienced that struggle firsthand. He worked with Chemie Linz and Imperial Chemical Industries, two of the first commercial PHA makers, during his PhD and postdoctoral years. He began his independent career at Tsinghua University in 1994 by partnering with Procter & Gamble to develop its PHA technology, which it sold to Danimer Scientific in 2007.

“I know every problem in this industry,” Chen says. And he’s confident that he and his team hold the solution: a special strain of salt-loving bacteria they’ve been honing over 15 years in their lab at the university to brew up bioplastics from waste sugar and acetate.

Other PHA makers use classic Escherichia coli or Pseudomonas bacteria, which require a carefully controlled and sterilized fermentation setup to avoid contamination by other bacteria, Chen says. His approach uses a type of Halomonas, an extremophile that thrives in high-pH, high-salt environments that potentially contaminating species cannot tolerate. Using fermentation conditions that only its specialized bacteria are hardy enough to live in means that PhaBuilder doesn’t need to worry about sterilization.

The engineered bacteria also grow more quickly and achieve higher cell density than other strains do, which means they make more material per batch, Chen says. “All the other bacteria . . . cannot compete with ours,” he says.

Though a bit of a latecomer to the PHA arena, “PhaBuilder kind of surprised me,” says Kristin Marshall of the advisory firm Lux Research. She thinks its extremophile-based technology has potential to simplify scale-up and to lower costs.

PhaBuilder makes three main types of PHA: rigid poly(3-hydroxybutyrate), elastic poly(3-hydroxybutyrate-​co-4-hydroxybutyrate), and flexible poly(3-hydroxybutyrate-co-3-hydroxyvalerate). They can be blended together to make plastics for a huge slate of potential applications, the company says.

The challenge will be forging the right partnerships to keep PhaBuilder and its bacteria growing to the point where they can put a dent in the market, Marshall says. The firm is already linking up with Solenis and Hengxin to make coated paper for packaging. Chen says PhaBuilder is also working on PHAs for disposable straws and cutlery, 3D printing, and medical implants.

In 2023, PhaBuilder announced that it would partner with the fermentation specialist Angel Yeast to use its engineered Halomonas in a production plant in Yichang, China. They expect to finish the first phase of construction later this year, start producing 10,000 metric tons (t) per year in early 2025, and increase annual production to 30,000 t by 2026. Marshall says the only PHA company to have exceeded double-digit production capacity so far is Danimer, at its plant in Winchester, Kentucky.

Chen’s ambitions don’t stop at outpacing other PHA companies, though. He talks about challenging PLA in about 5 years and perhaps even one day giving polyolefins a run for their money.

“We are very confident” that PhaBuilder will succeed, Chen says, because its technology is built on decades of history and persistence.