New projects on the site of a former oil refinery could create up to 460 new jobs in the coming years, with the help of cash from the UK and Scottish governments.

Scottish Energy Secretary Gillian Martin said the announcements by two firms of plans to create jobs shows a “long term, new industrial future at Grangemouth is achievable”.

Scottish biotech firm MiAlgae has revealed plans to create 130 direct full-time jobs in Grangemouth over the next five years – and support 180 further posts – by making fish-free Omega 3 supplements using leftover by-products from the whisky production process.

With the plans announced in the wake of the closure of what was Scotland’s only oil refinery back in April, MiAlgae is being helped with £1.5 million of funding from both governments.

Meanwhile, Celtic Renewables could create up to 149 jobs in Grangemouth by 2030 after it received £6.23 million of cash from Holyrood ministers for pre-construction work for a bio-refinery at Grangemouth to support the manufacture of “green” chemicals.

This work will see waste products from the food, drink and farming sectors converted into acetone, butanol and ethanol – chemicals used in everyday items such as cleaning products and nail varnish remover.

Union leaders at Unite welcomed the plans – but said politicians must now work to accelerate the projects as former refinery workers “can’t wait another five years for jobs to be made available”.

Unite Scottish Secretary Susan Fitzgerald said: “Unite welcomes the news that hundreds of new highly skilled jobs will be created in Grangemouth by companies in biorefinery and bioreactor projects with the support of government finance.”

But she insisted: “The job of government is to now accelerate the construction and operation of new projects because the highly skilled workers out of work in Grangemouth today can’t wait another five years for jobs to be made available. We need to harness every lever and unlock every pot of government finance to deliver a positive future for Grangemouth.”

However MiAlgae founder and chief executive Douglas Martin said breaking ground at Grangemouth “marks an exciting new chapter” for his company.

He added: “Our mission has always been to make a meaningful impact, tackling overfishing, reducing waste, and creating sustainable value from industrial by-products.

“This new facility is a huge step towards delivering that mission at scale, bringing new, high-quality green jobs to the local area, and helping Scotland lead the way in this exciting new biotech industry.”

The UK Government cash is coming from a £14.5 million funding pot for the Grangemouth area announced by Chancellor Rachel Reeves as part of last month’s Budget.

With the project also receiving Just Transition Funding from the Scottish Government, MiAlgae can now construct its first commercial-scale manufacturing facility.

Ms Martin said: “The Scottish Government will continue to do all that it can to support and promote local opportunities, jobs and growth, in the Grangemouth area. ”

Speaking about the proposals from MiAlgae and Celtic Renewables, she added: “Today’s announcement will help to support the creation of up to 460 roles directly and across the supply chain in Scotland, and help to highlight the wide range of viable alternatives for Grangemouth.

“They demonstrate that a long-term, new industrial future at Grangemouth is achievable, and will be vital to support the local workforce and community.

“This funding is only the start of the Scottish Government’s support to help safeguard Grangemouth’s role as a leading industrial cluster, and ensure the site continues to support our economy through new, green investment opportunities.”

UK energy minister Michael Shanks said MiAlgae’s project is a “step forward” for the area.

Speaking ahead of a ground-breaking ceremony at the Grangemouth site on Thursday, he said: “When we came into office there was no plan for Grangemouth. That’s why we quickly took action to secure the site’s long-term future, while supporting affected workers into new jobs.

“Today we’re taking another step forward as we back the first new project at the site, creating hundreds of new, decent jobs and attracting further investment in the area.

“This project, alongside the £200 million of funding pledged from the National Wealth Fund, is part of our clear strategy for Grangemouth’s industrial future. A strategy with workers, unions, businesses, and the wider community at its heart.”

Scottish Secretary Douglas Alexander said the £1.5 million investment will “support MiAlgae’s innovative green technology and boost jobs and investment in Grangemouth”.

He added: “The UK Government is backing Grangemouth’s future with real investment and a clear plan.

“We promised to secure the site’s long-term future and create good jobs, and that’s exactly what we’re doing – supporting new industries, creating opportunities, and ensuring this site remains a vital part of Scotland’s industrial heartland for generations to come.”

Mr Alexander said MiAlgae is “one of many projects” the Government is “working to bring to the site”.

Scottish Government funding of £600,000 is being given to Scottish Enterprise to support work to ensure Grangemouth is seen as attractive for new investors

Jan Robertson, director of Grangemouth transition at Scottish Enterprise, said: “Seeing MiAlgae break ground on its first commercial-scale plant, as well as announcing the latest stage in Celtic Renewables’ growth journey, are causes to celebrate.

“We also welcome the additional £0.6 million Scottish Government funding to accelerate our important infrastructure improvement work at Grangemouth, which will unlock further investment at the cluster and support the creation of new jobs.”