Biodegradable plastics (BPs), such as Poly Lactic Acid (PLA), has received much attention from the viewpoint of environmental protection and solid-waste management in agriculture field. Various microorganisms, including bacteria, fungi, and yeast, have been reported to degrade PLA by measuring the decrease in the turbidity of PLA dispersions. However, the results indicated that there are many microorganisms that can degrade PLA dispersions but not solid BPs. The objective in this study was developed a rapid and simple methods that more suitable for evaluating the degradation of solid PLA films. Evaluation of the relative PLA-degradation activity using dye-containing PLA films (dye-PLA assay) indicated Optical Density (OD600), and Total Organic Carbon (TOC). It can conclude that two methods are suitable for evaluation of the relative PLA-degradation activity using dyecontaining PLA films (dye-PLA assay). Moreover, enzyme solution from Aneurinibacillus migulanus had similar ability to proteinase K from Engyodontium album within 24 hrs at 30 °C.