Anaerobic desulfurization of ground rubber with the thermophilic archaeon Pyrococcus furiosus - a new method for rubber recycling

The anaerobic suIfur-reducing archaeon Pyrococcus furiosus was investigated regarding its capacity to desulfurize rubber material. The microorganism's sensitivity towards common rubber elastomers and additives was tested and several were shown to be toxic to P. furiosus. The microorganism was shown to utilize sulfur in vulcanized natural rubber and an increase in cell dens ity was obtained when cultivated in the presence of spent tire rubber. Etha nol-leached cryo-ground tire rubber treated with P. furiosus for 10 days wa s vulcanized together with virgin rubber material (15% w/w) and the mechani cal properties of the resulting material were determined. The increase in t he stress at break value and the decrease in swell ratio and stress relaxat ion rate obtained for material containing microbially treated rubber (compa red to untreated material) show the positive effects of microbial desulfuri zation on rubber.