REDUCTION OF SURFACE SULFUR UPON MICROBIAL DEVULCANIZATION OF RUBBER MATERIALS

Thiobacillus ferrooxidans, T. thioparus, Acidianus brierleyi and TH2 L und, an archaeal isolate, were tested for sulphur oxidising capacity o n ground rubber from spent car tyres. T: ferrooxidans converted 8% (w/ w) of the sulphur in cryoground spent rubber to sulphate in 20 days. D esulphurization of fresh made natural rubber was studied with scanning electron microscope with energy-dispersive x-ray spectrometer and ele ctron spectroscopy for chemical analysis. The average depletion of sul phur on the treated surface was 24% compared to the bulk region. Oxidi sed sulphur species were detected on the surface after microbial treat ment.