Microbial devulcanisation

Other work that has been carried out with microbial devulcanisation includes use of the microorganism Pyrococcus furiosus to carry out devulcanisation under anaerobic conditions. This type of bacteria reduces the sulfur in the crosslinks to hydrogen sulfide [108]. Another type of bacteria, Sulfolobus acidocaldarius, can be used to selectively cleave carbon-sulfur bonds to generate sulfate compounds that stay in the rubber and so the sulfur remains available for any revulcanisation treatments [109]. 

Waste Tyres Case Study - Summary TYR0008 - DART Microbial Devulcanisation, Waste Resources Action Programme, Banbury, UK, 2007. 

In this process, which has been in existence as a concept for at least 30 years and is often referred to as a microbial process, chemolithiotrophic bacteria in aqueous suspensions in the presence of oxygen can be nsed to selectively attack the sulfur crosslinks in the snrface of waste rnbber crumb particles. The process can also be regarded as a type of biodegradation process, the by-prodncts of which can inclnde elemental sulfur, sulfates, sulfides and snlfnric acid. Specific examples of the bacteria that have been used to devulcanise rubber in this way inclnde species of Thiobacillus, e.g., T. thiooxidans. 

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