Biodegradasi naftalena dengan penambahan yeast extract 0,5% (b/v) oleh isolat bakteri DRK 9.1 asal lumpur vulkanis di Desa Renokenongo, Kabupaten Sidoarjo = Biodegradation of naphthalene with addition of 0,5% (w/v) yeast extract by A bacterial isolate DRK 9.1 from volcanic mud in Renokenongo Village, Sidoarjo Regency