You can not use the clear-zone method of detecting LDPE degradation by microbes. Microbes (if at all they degrade this polymer) attack the other sustances like certain binders etc. The broth culture only can show you any degradation and that too you have to examine the film under a good microscope periodicall along with a negative control experiment.
Hi, Congratulations for your research hypothesis against Soil pollution. Here i have attached some articles for your reference this may be useful to you. All the best.