Biodesulfurization of vulcanized rubber by enzymes induced from Gordonia amicalisa

In this work, Gordonia amicalisa was used to treat two kinds of vulcanized synthetic rubbers, vulcanized isoprene rubber (v-IR) and vulcanized styrene butadiene rubber (v-SBR). The effects of microbial treatment on vulcanized rubbers were evaluated by changes of crosslinking density, sol fraction, morphology, element content and chemical group of treated rubber samples. The results showed that G. amicalisa can break CC bond mainly on v-IR and SS bonds mainly on v-SBR. After microbial treatment of 20 days, the crosslink densities of v-IR and v-SBR decreased by 13.7% and 22.1%, respectively. The carbon content on v-IR surface was decreased by 9.1%. FTIR analysis showed that CC bonds transferred into CO bonds, indicating the main chain scission. Regarding to the v-SBR, sulfur content on its surface was decreased by 22.9%, SS bonds were broken and SO producing, indicating the sulfur crosslink scission. Furthermore, the inducing mechanism of desulfurizing enzyme produce from G. amicalisa was investigated. v-SBR and v-IR were used as enzyme inducers, and dibenzothiophene was used as substrate reacting with desulfurizing-enzyme. The liquid chromatography and ultraviolet spectrum analysis showed that v-SBR was the specific substrates that can induce G. amicalisa to secret desulfurizing enzyme, making desulfurizing reaction happen.