Microbial Degradation of Poly Lactic Acid (PLA) by Aneurinibacillus aneurinilyticus

Poly lactic acid (PLA) is one of the most promising biodegradable plastics. It has various types Of standard testing methods such as visual observations, weight loss measurements, clear-zone formation, and enzymatic degradation. However, the number of study on synthesized biodegradable plastics and its degrading microorganisms is still limited. The objective of this study was to screen the microorganisms that have ability to degrade PLA in solid and liquid medium. The analyses include the comparison with Poly Ethylene Terephthalate Glycol (PETG), observation of PLA films morphology by Scanning Electron Microscope (SEM) and bacterial identification. The strain was identified as Aneurinibacillus aneurinilyticus by the API 50 CHB/E medium test analysis. It significantly degraded PLA film (33.87%) within 30 days in liquid medium. Furthermore, the rough and hemispherical holes were apparently found on the film surfaces. In addition, the studies on systems of degrading activity mechanisms are currently in progress to produce the effective microorganisms that will be beneficial for environmental biodegradable plastics development.