Microbial Scission of Sulfide Linkages in Vulcanized Natural Rubber by a White Rot Basidiomycete, Ceriporiopsis subvermispora

Abstract

A white rot basidiomycete, Ceriporiopsis subvermispora, degraded vulcanized natural rubber (NR) sheets on a wood medium. The fungus decreased the total sulfur content of the rubber by 29% in 200 days, accompanied by the cleavage of sulfide bonds between polyisoprene chains. X-ray photoelectron spectroscopy (XPS) demonstrated that C. subvermispora reduced the frequency of S-C bonds by 69% with a concomitant formation of S-O bonds during the culture period. Dipolar decoupling/magic angle spinning (DD/MAS) solid state 13C NMR revealed that the fungus preferentially decomposed monosulfide bonds linked to a cis- and trans-1,4-isoprene backbone but the cleavage of polysulfide bonds was also observed. In contrast, no decrease in weight or devulcanization of rubber was observed in cultures of a white rot fungus, Dichomitus squalens. The oxidative cleavage of sulfide bonds by C. subvermispora demonstrates that ligninolytic basidiomycetes are potential microbes for the biological devulcanization of rubber products.

Microbial Desulfurization of Ground Tire Rubber by Sphingomonas sp.: A Novel Technology for Crumb Rubber Composites

“…could reduce sulfur content of GTR and the similar results were also obtained by using other bacterium for rubber desulfurization. Such as Sulfolobus acidocaldarius used for rubber desulfurization released 13.4% sulfur of rubber material during 7 days [25], the fungus can decreased the total sulfur content of the rubber by 29% in 200 days [15], and sulfur content of natural rubber was reduced by up to 30% compared to that of the untreated rubber in the case of the 30-day microbial desulfurization by T. perometabolis [26]. The binding energy was 166-168 eV, 169-171 eV, and 164 eV for sulfite, sulfate, and sulfur, respectively [27].…”

“…In recent years, many researches have been focused on the microbial desulfurization of ground rubber with microorganisms that exhibit biological activity towards sulfur and are capable of oxidizing sulfur to sulfate [9][10][11][12][13][14][15]. Bredberg [9] investigated and reported on the ability of sulfur-oxidizing bacteria (Acidithiobacillus) and sulfurreducing bacteria (P. furiosus) to break sulfur cross links in vulcanized rubber materials.…”

Improvement of the properties of natural rubber/ground tire rubber composites through biological desulfurization of GTR

“…In recent years, several microorganisms that exhibit biological activity towards sulfur have been used for the desulfurization of ground rubber [11][12][13][14]. These microorganisms can decrease the sulfur content or oxidize sulfur to sulfate, increasing the reactive sites on the surface of ground rubber.…”

Effect of Temperature on Devulcanization of Waste Sidewall Rubber by Supercritical Ethanol

“…1 Various types of devulcanizing routes have been studied so far in order to improve the quality of the recycled products, such as chemical method, mechanical process, microwave technique, ultrasonic method and microbial method. [2][3][4][5][6][7][8][9][10][11][12][13] However, some processes have weaknesses such as environmental pollution and low efficiency.…”