RNA analysis of anaerobic sludge during anaerobic biodegradation of cellulose and poly(lactic acid) by RT-PCR–DGGE

Abstract

Here, we apply a method to evaluate the anaerobic biodegradability of bioplastics, such as polycaprolactone and poly(lactic acid) (PLA), in aquatic (slurry) conditions at 55 °C. Previous reports have suggested that some of the microorganisms participating in the anaerobic biodegradation of cellulose and PLA differ. However, polymerase chain reaction–denaturing gradient gel electrophoresis (PCR–DGGE) analysis was ineffective at detecting the microorganisms involved in the anaerobic biodegradation of cellulose and PLA. In this study, reverse transcription-PCR–DGGE analysis was employed instead. New DGGE bands appeared during the anaerobic biodegradation of cellulose and PLA, and some of these DGGE bands differed between the anaerobic biodegradation of cellulose and PLA, indicating that some of the microorganisms involved in these two processes differed. These results and those of our previous study therefore show that it is necessary to describe, not the anaerobic biodegradation rate of cellulose, as generally used at present, but the anaerobic biodegradation rate of plastic in the plastic anaerobic biodegradation test, to evaluate the sludge condition containing plastic anaerobic biodegradation activity in the sludge used in the anaerobic biodegradation test of plastics at 55 °C.