Brazilian state-controlled oil and gas major Petrobras (<a href="https://www.b3.com.br/en_us/market-data-and-indices/data-services/market-data/quotes/?tvwidgetsymbol=BMFBOVESPA%3APETR4" target="_blank">BVMF:PETR4</a>) announced on Tuesday it is holding its first public call for biomethane acquisition proposals.