The New York developer who failed to win local permits to build Maine’s tallest hotel at Spring Point recently purchased the largest empty office building in South Portland, and has started to renovate it.

John Cacoulidis paid just under $10 million for 300 Southborough Drive, near Payne Road, according to Thomas Moulton, partner with the Dunham Group, which brokered the sale. The 116,500-square-foot office building had been vacant since the Unum Co. moved out 18 months ago.

I write about the property transaction and plans by Cacoulidis for the building in this week’s edition of the Current newspaper.

The seller was a Middle Eastern royal family represented by a Boston company, Moulton said. The property owner was listed in South Portland tax records as Scarborough Holdings LLC, and the city had valued the property at $15.9 million.

Scarborough Holdings owned the building since 2003, leasing it to Unum, the original property owner.

Moulton said renovations will focus on energy-efficiency, with a goal to bring the building to industry-level standards, known as LEEDS.

Caccoulidis previously had tried to build a hotel complex, hospital and convention center on 22 acres he owns on South Portland’s waterfront. He had proposed connecting the complex to Portland by using an air tram across that people would take across the harbor.

Caccoulidis and his wife live part time on a private island they own off the coast of Cumberland.