* Judge says Barclays may recover $1.5 bln assets
* Trustee plans to appeal, several claims rejected
* Barclays bought part of Lehman during 2008 crisis (Adds comment from lawyer for Barclays)
By Caroline Humer and Jonathan Stempel
June 5 (Reuters) - Barclays Plc is entitled to recover roughly $1.5 billion of disputed assets related to Lehman Brothers Holdings Inc's bankruptcy, a U.S. federal judge said, reversing a decision by a federal bankruptcy judge.
Tuesday's decision by U.S. District Judge Katherine Forrest in Manhattan is a setback for James Giddens, the trustee of Lehman's brokerage unit Lehman Brothers Inc, because it may reduce the amounts available for customers.
Forrest said Giddens is not entitled to billions of dollars of assets, including "clearance box" assets held to facilitate the clearance of securities trading. She also rejected some claims by Barclays, including for money in customer accounts.
The decision partially reversed a February 2011 ruling by U.S. Bankruptcy Judge James Peck, who oversaw Lehman's bankruptcy.
Giddens said he expects to appeal, adding that "we strongly believe that the former customers of Lehman Brothers Inc are entitled to these assets." He said the decision does not affect his plan to make a "substantial" payout to customers this year.
Jonathan Schiller, a lawyer for Barclays, said: "We are gratified by the court's decision today confirming that Barclays is entitled to the Lehman assets it purchased."
The dispute is one of many arising from the British bank's hurried $1.85 billion purchase of most of the Lehman unit's North American operations on Sept. 20, 2008.
That purchase occurred five days after the Chapter 11 bankruptcy filing by Lehman, a seminal event in the 2008 global financial crisis.
Peck last year also ruled that Lehman's parent could not recover an $11 billion "windfall" that it said Barclays received, saying the need to avert "an even greater economic calamity" outweighed any imperfections in the sale process.
In her decision, Forrest said the $1.5 billion of assets related to exchange-traded derivatives at the Lehman brokerage unit.
Lehman once had $639 billion of assets, making its bankruptcy by far the largest in U.S. history. It emerged from Chapter 11 in March.
Giddens is also the trustee for the brokerage unit of MF Global Holdings Ltd, the commodities broker once run by former New Jersey governor Jon Corzine.
The cases are Barclays Capital Inc et al v. Giddens, U.S. District Court, Southern District of New York, Nos. 11-06052, 11-06053. (Reporting by Caroline Humer and Jonathan Stempel in New York; Editing by Gary Hill, Dale Hudson and Tim Dobbyn)