SAO PAULO, Aug 17 (Reuters) - The owner of Burger King Brazil, Zamp SA, said on Wednesday its board of directors opposes Abu Dhabi state investor Mubadala Capital LLC's takeover bid for the firm, voicing its objection weeks before shareholders decide on the deal.

Zamp, previously known as BK Brasil Operacao e Assessoria a Restaurantes SA, is the master franchisee of the Burger King brand in Brazil, operating around 850 stores.

In early August, Mubadala launched a tender offer to purchase 45.15% of Zamp at 7.55 reais per share, which would lift its stake in the company to 50.1%.

In a securities filing, Zamp said it hired investment bank BTG Pactual as its financial adviser on the deal, which has established that a fair price would be in the range of 9.96 to 13.47 reais per share.

"The company's board of directors expresses an opinion against the acceptance of the offer by its shareholders," Zamp said.

Since the announcement, shares in the firm are up 35%, at 8.40 reais.

Zamp's shareholders will decide whether to sell its stakes or not in a tender set to take place on Sept. 15 in the Brazilian stock exchange B3. (Reporting by Peter Frontini Editing by Chris Reese and Leslie Adler)