The role of microorganisms in biodegradation of chitosan/tannic acid materials

High utilization of thermoplastic polymers with low degradation rates as packaging materials generates a large amount of waste. Therefore, it should be replaced by natural polymers that can be degraded by microorganisms. In this paper, chitosan (CTS)/tannic acid (TA) materials in the weight ratios of 80CTS/20TA and 50CTS/50TA were prepared as potential packaging materials. The results showed that these materials were similarly degraded in soil and compost. However, in comparison to 50CTS/50TA, 80CTS/20TA was slightly better degraded in soil. After 14 days of biodegradation, the chemical structure of materials was changed resulting from adhesion of the microorganisms. The smallest changes were observed on 80CTS/20TA film. Bacterial species were collected and identified from materials after the degradation process. Microorganisms with the highest hydrolytic activity were chosen for the degradation study. Biodegradation and hydrolytic activity were observed only in a few strains, which indicate difficulties in material degradation. Soil bacteria degraded the films better than bacteria isolated from the compost. This study showed also that consortia of bacteria added to soil and compost had a positive effect on the biodegradation of the tested materials and increased the biodegradation of these materials in the studied environments.

Automated summary

In this study, chitosan and tannic acid were used to prepare potential packaging materials, which were found to degrade similarly in soil and compost, with 80CTS/20TA showing slightly better degradation in soil compared to 50CTS/50TA. Changes in the chemical structure of the materials after biodegradation were observed, with microbial adhesion affecting the degradation process.