Efficiency of renewable plastic material degradation using effective microorganisms in aerobic conditions

Abstract

Studies were conducted to establish a simulated system based on the aerobic biodegradation of renewable plastic materials (cellulose, Poly lactic acid (PLA), and bio-base). The experiment consisted of carrying out biodegradation by using a reactor. The experiment was tested at 28 days under the following conditions: the control parameter of air flow was 60 mL/min, the humidity was 60-80%, and pH ranged from 7.5-8.5. The results indicated the analytical carbon dioxide (CO2) and weight loss. It was found that the effective microbes had been able to degrade the renewable materials, except for the bio-base. The EM had been able to degrade PLA and Cellulose at 4.51±0.50%and 40.53±2.15, while the weight loss of the PLA and Cellulose had been 5.24±0.85% and 42.65±3.55%. The EM had secreted cellulase enzymes to decompose the cellulose, and the enzymes had caused catalytic reactions, which, in turn, had degraded the cellulose. Because cellulose has organic carbon, the cellulose test showed high degradation. The EM had been able to degrade the cellulose because the EM consisted of aerobic and anaerobic microbes that had contributed to the degradation organic compounds. The result of the observations indicated that cellulose had torn after 28 days. However, the PLA had only slightly changed, while the bio-base had shown no change at all. Moreover, SEM observation showed that the PLA and the cellulose had been damaged. The EM were found to be growing on surface of two materials and were also growing inside of the materials. Meanwhile, no damage was found on the bio-base at all. The EM had been able to degrade the renewable materials. Cellulose is the material with the highest degradation. It is, therefore, possible that EM have the ability to degrade biodegradable plastics.

Keywords

• renewable plastic material
• bio-base
• poly lactic acid
• bioplastics
• effective microorganisms