Bioprospecção de microrganismos biodessulfurizantes de borracha vulcanizada de pneu inservível

Abstract

Tires have great importance, but have become a risk to public health and the environment due to the characteristics conferred by the rubber vulcanization and other components. One of the ways of reusing the tyre is rubber recycling through devulcanization. Thus, the objective was to isolate microorganisms from mechanic shop’s waste and assess their desulphurization of vulcanized rubber (VR) capacity. With selective enrichment using DMSO, two bacteria named D1 and DAF were isolated, later submitted to biochemical, metal resistance and antibiogram tests. Preliminary to the tests, fungus contamination was observed, which revealed to be from BV, being isolated and included in the protocol. It used 1% (w/v) of granulated tire rubber (BP-III) asepsis with 70% alcohol in a culture flask. Each microorganism was added with Bushnell-Haas medium without SO4-2 (BH-s) to a flask, one had no microorganism added, another contained only medium and were incubated in a shaker at 30ºC, 130 rpms. Biochemical tests indicated D1 as Pseudomonas sp. The molecular method identified DAF as Staphylococcus warneri and the fungus as Fusarium chlamydosporum. Bacteria showed tolerance to the metals tested. The D1 antibiogram had comparative data for five antibiotics, none of which were tolerant, while DAF showed sensitivity to eight. D1 had a greater amount of SO4-2 in the medium than DAF. This and the fungus degraded the rubber. However, the fungus has greater potential for desulfurization. Thus, the microbial capacity to desulfurize VR was observed, a promising and preferable method for tire recycling as it is environmentally friendly and cost-effective.