The pair were also shown the fermentation process where dye is produced in a smaller quantity and then scaled up.
David Clarke, the head of fermentation at the company, said the process was just like brewing.
He said: “Whenever people see scientific equipment and scientific process it’s always interesting… the basis of what we do is very, very simple so I think for people to understand that and engage with that is great.
“It’s always a big boost to see famous people… I think the team are very proud of what they do and very proud for them to come and visit us.”
The Prince of Wales’ Earthshot Prize, gives £1m to five winners to offer the best solution to some of the world’s biggest climate challenges.
While past ceremonies have been held in London, Boston, Singapore and Cape Town, this year’s ceremony is due to take place in Brazil in November.
The prince complimented the staff on their “fantastic” work and apologised for any “stupid questions” he had asked.
“It’s going really well, and it’s really exciting,” he said.