The reason might be the metabolism of the particular isolate. As this Pseudomonas sp. is isolated from a location with rich organic nutrients from sewage sludge, it may have the ability to utilize utmost organic carbon. Therefore, natural polyethylene served the bacteria with its additional vegetable starch ingredient which led them to consume natural polyethylene more rapidly than the synthetic ones. With our findings, we assume that the bacteria were able to utilize natural polymers faster than the synthetic ones because less metabolic activities are sufficient enough to dissociate the carbon backgrounds of natural polyethylene than the complex enzymatic reactions that are required for synthetic polymers.