Brazilian beef processor JBS has made a verbal buyout offer for Sara Lee Corp and is expected to submit a written proposal in the next 24 hours, two sources familiar with the situation said.

JBS made its verbal overture on Monday evening, the sources said. Bloomberg reported that JBS had indicated the offer would be around $21 a share.

Private equity giant Blackstone Group is involved in JBS's pursuit of Sara Lee, a separate source said. Under one scenario, Blackstone would acquire Sara Lee's beverage unit if the Brazilian meat company's bid succeeds, the source said.

That would leave JBS with Sara Lee's meat unit.

The future of Sara Lee, whose brands include Jimmy Dean sausages and Senseo coffee, has been in question for some months. It has been functioning with an interim chief executive since August when Brenda Barnes left after suffering a stroke.

Buying Sara Lee's meat business could offer a home for the trimmings of JBS's cattle, poultry and pork slaughtering operations. JBS could further gain by turning into a key supplier of meats to rival food processors.

Meanwhile, Blackstone could benefit from the beverage business' strong profit margins and well-known international coffee brands.

U.S.-based Sara Lee, valued by analysts at about $12.5 billion, has been examining various options such as selling itself or splitting itself up into meat and beverage units.

The company's board is scheduled to meet on Wednesday and Thursday, one source said, and is expected to examine the bid alongside a competing proposal from a group of private equity firms.

The Downers Grove, Illinois-based company has indicated it would seriously consider a bid of roughly $20 per share in order to continue talks with a suitor, a separate source familiar with the situation said. The source was not authorized to speak to the media.

A rival bid was submitted already from a group of private equity firms including Apollo Global Management , Bain Capital and TPG Capital , which values the coffee and meat company at up to $20 a share or nearly $13 billion, a source previously told Reuters.

If a private equity deal is successful, the deal would be among the largest leveraged buyouts since the credit crisis.

Sara Lee will also compare the takeover bids with a plan to split the company into separate meat and coffee units, a source previously told Reuters. If takeover bids fail to meet Sara Lee's benchmark, the company will pursue a breakup, that source said.

The sources declined to be identified by name because the situation is not public.

JBS, along with a group of other companies, has arranged a financing package to bid for all or parts of Sara Lee, a source previously told Reuters.

Sara Lee and JBS could not immediately be reached for comment. Blackstone declined comment.

Sara Lee shares closed at $19.64, up 7 percent, on the New York Stock Exchange on Tuesday afternoon. Blackstone shares were down 1.13 percent at $15.76.

(Reporting by Jessica Hall and Megan Davies in New York, and Guillermo Parra-Bernal in Sao Paulo; editing by Maureen Bavdek, Matthew Lewis and Bernard Orr)