3.2 Total Organic Carbon (TOC) In the presence of PLA film, the isolates grew well and utilized the soluble carbon source (yeast extract) present in the medium and resulted in the depletion of TOC values at the initial stages. Later the TOC values increased progressively. Two fold increase in TOC was observed on day 15 indicating the release of organic carbon from the polymer. The TOC value dropped even below the initial value after 25 days of degradation. The decrease in TOC values may be due to microbial assimilation of substrate and reveals the utilization of PLA as carbon source. Similarly, pH of the basal medium was dropped due to the release of lactic acid (Table 2). 3.3 Scanning Eelectron Microscopy (SEM) SEM was used to observe changes in PLA film after incubation with the isolates MS-1, MS-2 and MS-3.