Conversion of indole to oxindole under methanogenic conditions

Abstract
When indole was incubated under methanogenic conditions with an inoculum of sewage sludge, the chemical was metabolized within 10 days temporary formation of an intermediate was observed. The metabolite was isolated by thin-layer chromatography and determined to be 1,3-dihydro-2H-indol-2-one (oxindole) by UV spectroscopy (.lambda.max, 247 nm) and mass spectrometry (m/z, 133). The methane produced (net amount) indicated nearly complete mineralization of indole.