by Patricia Sellers

You might call Al Koch the world's biggest trash collector. As bankrupt General Motors (GM) splits into two parts -- New GM, containing Chevrolet, Cadillac, Buick, and GMC, and Old GM, containing designated bad assets such as Pontiac, Saturn, Hummer, Saab -- Koch is the hired gun who's supposed to create value from that latter lot.

Bringing "New GM" out of bankruptcy will be difficult enough. Why would anyone take the tougher slog at "Old GM"?

This is what Koch does -- the toughest turnarounds. He's vice chairman at restructuring consultancy AlixPartners, which works on saving sick comapnies globally but has been a Detroit mainstay for decades. AlixPartners' clients have included DeLorean's creditors in 1984, Detroit (the city itself) in 1994, and Kmart in 2002.

Koch, now 67 and a 14-year veteran of the firm, has served as interim CEO of crippled companies such as video-game distributor Handleman (HDLM) and manufactured-home builder Champion Enterprises (CHB). But his most memorable job was at Kmart in 2002. Kmart was the largest retail restructuring in history and, as it turned out, one of AlixPartner's big successes.

As Kmart's interim CFO through its bankruptcy, Koch got lucky. When I interviewed him in late 2005 for a story about investor Eddie Lampert, he said that he and his restructuring-expert colleagues had never heard of this young investor who had swooped in and bought Kmart bonds at 40 cents on the dollar. "To most people, Kmart looked like a pile of trash," Koch said. "We were told that this hedge fund guy had bought a huge portion of Kmart and wanted to get it out of bankruptcy fast."

Lampert pressed Koch and the other restructuring pros, who were earning $10-20 million a month during Kmart's bankruptcy, to exit Chapter 11 quickly. Lampert argued that neither customers nor management talent would be attracted to a bankrupt Kmart. The company emerged from bankruptcy in May 2003, a year ahead of schedule. Lampert, who had invested some $800 million for a 54% ownership stake, merged Kmart with Sears two years later to form Sears Holdings (SHLD).

Old GM won't be as smooth or as quick as Kmart was. As my colleague Alex Taylor notes, "new GM" will have an incentive -- from the U.S. government, new owner of a 60% stake --  to exit Chapter 11 rapidly, possibly in 60 to 90 days. The Old GM restructuring, meanwhile, could take years.

As Old GM's chief restructuring officer, Koch will be negotating separation agreements with New GM and commandeering efforts to unload or liquidate those dud brands such as Saturn and Hummer.

His influence could turn out to be broader than his marching orders designate. After all, he's worked with GM several times over the years. These past few months, he's helped negotiate the sale of New GM assets to the government. Now he's reporting to CEO Fritz Henderson and to GM's board as well. As a guy who lives and dies by finding value in junk, Koch surely won't take his shot at making history lightly.