Agricultural mulch film of poly(lactic acid) (PLA) has been prepared under industrial conditions by the extrusion blown film method with modified properties using poly(hydroxibutyrate) (PHB) and reactive compatibilizer maleic anhydride (MA). Processing parameters and blend composition have been optimized based upon processability and mechanical properties of the final materials. Because PLA is a biopolymer, evaluation of service life period of the mulch film is very much important. Sustainability of the film has been analyzed by keeping the films in a weatherometer, which can create accelerated weather conditions, followed by mechanical testing at regular intervals. Similarly, variation in compostability has been analyzed as per the American standard for test method, ASTM D 5988, using vermi-compost. In addition, specific microbial action on the mulch films also has been analyzed using bacteria Berkholdaria cepacia (B. cepacia), which is selective in particular toward PLA degradation and in mixed fungal inoculums.