The Process of Natural and Styrene–Butadiene Rubbers Biodegradation by <i>Lactobacillus plantarum</i>

Abstract

The ability of Lactobacillus plantarum to degrade different mixtures of styrene–butadiene and natural rubbers was investigated. In experiments, 12 various compositions of rubber waste mixtures were investigated. Lactobacillus plantarum cultivation was carried out in a medium with the addition of individual mixtures at the temperature of 30 °C for 14 days. The presence of cellulose on the surface of bioreactors indicated the activity of bacteria. After cultivation, the rubber mixtures were tested again. Analyses of the elemental composition and mass balance of waste were carried out. The experiments showed that the culture media supplemented by various natural rubber mixtures allowed bacteria to produce bacterial cellulose. The mean thickness of bacterial cellulose was 3–6 mm after 14 days of culturing. In samples where the cellulose appeared, about 4% average mass loss was observed. The average carbon content in the rubber material used as the carbon source for bacteria, before the culture process, was about 89.07–95.40%. After 14 days of culturing, the carbon content was reduced from 31.15% to 56.45–65.7%.

Keywords

• rubber waste
• natural rubbers
• styrene–butadiene rubbers
• degradation process
• <i>Lactobacillus plantarum</i>