SAO PAULO, Brazil (CNN) -

Strolling between shelves crammed with his records, Zero Freitas pauses and finds another piece of music that he just must take home.

He is walking through a warehouse where there are about 250,000 records. The room seems to stretch away with his records but it is only a fraction of the collection. Most of his five million records are in a former candle factory nearby, and another 100,000 are kept in his home -- for personal listening.

Freitas pulls from the shelf a copy of "The Country Blues of John Lee Hooker." "Marvelous," he chuckles. "This is rare. I'm going to have to take it home."

Which is a problem of sorts. Freitas is trying to consolidate and catalog his massive vinyl collection, but every day he ends up finding some treasure or other that he sneaks out of the cataloging collection and off to his private stockpile at home.

"What I have at home is what I have mined over the course of my life," Freitas tells CNN at his warehouse in Sao Paulo. "These days, it's things that appear out of nowhere, that I didn't even know I was looking for."

Freitas, 62, calls himself "a hunter of lost sound." He is a Brazilian bus magnate whose obsession has turned him into the owner of the largest known record collection in the world -- an estimated five million singles, albums and old 78s.

"Everyone thinks I'm obsessed with albums," he says. "But really it's an obsession with memory and history, of Brazil and all of human kind."

For years he bought records -- sometimes individual albums and sometimes entire vinyl collections -- unnoticed.

In high school, he already had 3,000 and by the time he was 30 he had amassed roughly 30,000 albums. A recent agreement with Brazilian authorities has allowed him to import whole shipping containers full of aging records and his collection has ballooned.

When major international collectors or iconic shops like New York's Colony Records sold off their stockpiles, nobody really knew where they were going.

But earlier this month, the New York Times revealed that Freitas was the eclectic buyer behind many of the transactions.

"Now I'm being hunted," Freitas laughs. He says most of the interest has come from sellers, but also from people searching for an obscure piece of music.

He says: "90 percent of the time, people are looking for something from their childhood. It's often culturally irrelevant music, but for that person extremely important.

Freitas now wants to make his records available to the public as early as next year -- in a kind of listening library that he'll call a Musical Emporium.

He has hired 17 interns to help him. Most of them history students.

Wearing plastic gloves and surgical masks, they clean and dust the vinyl discs, photograph the covers and painstakingly catalog each album.

They get through about 500 records a day and have so far cataloged about 250,000. A drop in the bucket.

Freitas thumbs through some of the records from his personal collection that he brought in to show us: "Wedding Album" by John Lennon and Yoko Ono; a signed copy of Duke Ellington's "New Orleans Suite;" and not one, but four copies of the first album made by Brazilian crooner, Roberto Carlos, "Louco por Voce."

"Just the other day, we found an autographed Arthur Rubinstein that I didn't even know existed!" he says, referring to the classical American pianist.

But one of his most treasured discoveries, he says, is a rare recording of soprano Bidu Sayao, signed by the composer Heitor Villa-Lobos. Freitas bought it on eBay for one dollar.