Months ago, we wrote about how Prolific Machines, one of IndieBio’s fastest-growing startups and the record-holder for fastest seed round in IndieBio history—has the key to cell cultured meat via its unique optogenetic approach. We still believe it (along with the technology’s potential for other applications in food and medicine), and tons of leading investors do, too—to the tune of $55 million in new Series B financing.

So what’s optogenetics, and how is Prolific Machines harnessing it? Optogenetics refers to a biological technique used to control the activity of neurons or other cell types with light. Light can instantly turn “up” or “down” important cellular processes, allowing precise control over exactly when and for how long bioprocesses, like gene expression, receptor activation, and enzyme activity are active.

“For the last few decades, the way that we’ve been controlling cells is with molecules,” Prolific co-founder Denis Kent told TechCrunch. “Those molecules could be chemicals or they could be proteins. We add these molecules into the bioreactors and hope for the best.”

The company believes its light-powered bioreactors are a far better, more precise method to cell growth.

The Series B was led by the Ki Tua Fund, the corporate venture arm of Fonterra, with participation from Breakthrough Energy Ventures, Mayfield, SOSV, Shorewind Capital, Darco Capital, Conti Ventures and In-Q-Tel (IQT). The funding brings Prolific Machines’ total raised to date to $86.5 million.

The team plans to use the funding for commercialization and customer acquisition. “We’re now transitioning from having proved that this is working to giving this to people,” he said in the same TechCrunch interview. “We started engaging with some commercial partners, but we are not going to announce that quite yet.”