Estimation of the Microbial Degradation of Biodegradable Polymer, Poly(lactic acid) (PLA) with a Specific Gas Production Rate

Biodegradable polymers and plastics have been investigated extensively and commercial applications of poly(lactic acid) (PLA) are being implemented. A feasible and rapid estimation of the biodegradability is urgently needed to satisfy environmental regulations and consumer's desire considering the market situation. On the other hand, an estimation of the biodegradability of polymers normally requires a long time for measurement and there is less standardization, making it difficult to analyze and compare. This study examined the microbial degradation of PLA with anaerobic digester sludge. The gas production and by-product formation from PLA degradation were analyzed to assess the extent of biodegradation. The different specific surface areas of the PLA granules results in different gas production rates and degradation capacities, while an increase in surface area tends to increase the level of gas production. The specific CO2 and CH4 production rates were estimated based on the total surface area to quantify the biodegradability of PLA. The results showed that a rapid and feasible testing method of biodegradability is possible, and can be implemented to develop and optimize environmentally friendly plastics and polymers.