By Tatiana Bautzer and Gram Slattery SAO PAULO/RIO DE JANEIRO (Reuters) - A consortium led by France's Engie SA submitted the highest offer for a major gas pipeline unit owned by Brazil's Petroleo Brasileiro SA, the state-run oil firm said on Friday, as the company's biggest divestment draws to a close. In a filing, Petrobras, as the company is known, said the Engie consortium, which includes Canada's Caisse de Dépôt e Placement du Québec, presented an $8.6 billion bid for 90 percent of the TAG gas pipeline unit in northern and northeastern Brazil.