Accelerating degradation of natural rubber latex gloves by a consortium of microorganisms in an agricultural soil sample

The complexity of the vulcanized rubber makes it difficult to be degraded by microorganisms. It is believed that a microbial consortium can improve the efficiency of the biodegradation process. Fertile soil houses a plethora of microorganisms with innate ability to adapt to various chemical substances come into contact with its texture. Consequently, a soil sample which was in direct contact with tire wastes for more than 13 years was employed in this work to enhance the biodegradation of natural rubber (NR) gloves. The active soil microorganisms associated with the NR latex degradation were isolated and identified using 16S rRNA gene sequencing method. The biodegradation of NR gloves in the soil sample containing these bacteria was investigated and the results represented 87% and 79% weight loss in the examination and surgical gloves after 12 months of treatment, respectively. The total biodegradation was achieved after 13 and 15 months which was nearly half of the reported time in the landfill processes. Thermal gravimetric analysis (TGA) showed 15% incremental weight decrease for the treated samples after three months in comparison with the blanks and the FT-IR spectra approved the breaking of the cross-link sulfur bonds as well as the formation of carbonyl groups which indicated oxidative cleavage of double bonds of the polymer chain. A chemical mechanism for the biodegradation was suggested based on the obtained results to explain the higher efficiency of biodegradation in this work.