(SeeNews) - Sep 19, 2012 - Petrobras Biocombustivel (Pbio), the biofuels subsidiary of Brazil's oil and gas giant Petrobras (SAO:PETR3), is negotiating with local sugar and ethanol producers Sao Martinho (SAO:SMTO3) and Acucar Guarani SA the installation of a commercial-scale cellulosic ethanol production plant.