More than five years after the lights were switched off at Adelaide's Holden plant, the site is now on the verge of becoming another manufacturing and export powerhouse.

But, instead of sedans and station wagons, it is thousands of tonnes of mushrooms that are set to begin rolling off the production line.

A new $110 million facility will turn the former car hub into what the SA government has described as the "exotic mushroom capital of Australia", run by local producer Epicurean Food Group.

The site will supply produce to supermarkets and restaurants, but also will have an on-site lab and commercial kitchen to turn second-rate mushrooms into vegan products like burger patties.

"We start with white oyster mushrooms, then we will go into shiitake, enoki and king oyster," Epicurean Food Group chief executive officer Kenneth King said.

Six growing rooms will start producing 20 tonnes of mushrooms per week from late February, before output ramps up to an estimated 20,000 tonnes of raw mushrooms and mushroom products per year.

"[We want to] introduce a lot of the population to the product, bring it to the menu, bring it to their daily consumption because they're very healthy.

"But also, we value-add — we make burgers and balls and sausages, crumble, meals, and that gives us the ability to freeze them down and export."

A current workforce of 37 full-time employees — which includes ex-Holden workers — is expected to expand to about 350 over the next 15 months.

"I've got a number of ex-Holden people and they're wonderful workers. They've been really well received," he said.

Mr King said the farm would be the largest of its kind nationally by the time it is complete, which is expected to be around mid-2024.

"This will be the only truly professional-style exotic mushroom farm in the country. There are lots of others, but no-one has ever gone to the extent that I have," he said.

"In Australia … the industry has never had the ability to grow 52 weeks of the year, so we look for some real strong growth based upon the fact that we can provide right across the spectrum.

"This is a very developed farm, it's very high tech. It costs money to build, but you get a result."

SA Trade and Investment Minister Nick Champion said the mushroom farm joined other enterprises on the site, including a home-battery producer and fuel depot.

"South Australia already accounts for some 17 per cent of Australia's mushroom production and this will help to drive that figure up," he said.

"It creates a really good supply chain, not just mushroom supply into supermarkets and the like but also into high-end restaurants."

The site will include specially built growing rooms with columns up to 13 metres high, and Mr King said there were other flow-on effects, including environmental ones.

"It's a very circular business," he said.

"We take a waste product from the barley farmers and the wheat farmers, we bring that here, we turn that into high-value substrate, we then return that back to the system via a green digester and we make green energy."