NOVELTY - Synthesizing thermoplastic biopolymer comprises: acquiring an activated sludge by treating a waste water; acclimatizing the activated sludge and a synthetic waste water in a sequential batch reactor for 60 days; pretreating a diazotrophs with carbon dioxide in an incubator at a preset temperature for 30 days; enriching the acclimated activated sludge taken from the sequential batch reactor with pretreated diazotrophs taken from the incubator for 2 days in a polymer production reactor to produce a thermoplastic biopolymer; and purifying and collecting the thermoplastic biopolymer.    USE - The method is useful for synthesizing thermoplastic biopolymer.    ADVANTAGE - The method provides thermoplastic biopolymer with increased efficiency and decreased cost of production in an environmentally friendly manner.    DETAILED DESCRIPTION - Synthesizing thermoplastic biopolymer comprises: acquiring an activated sludge by treating a waste water; acclimatizing the activated sludge and a synthetic waste water in a sequential batch reactor (101) for 60 days; pretreating a diazotrophs with carbon dioxide in an incubator at a preset temperature for 30 days, where the incubator is a secondary carbon source reactor (102) and the preset temperature is 24 degrees C; enriching the acclimated activated sludge taken from the sequential batch reactor with the pretreated diazotrophs taken from the incubator for 2 days in a polymer production reactor (103) to produce a thermoplastic biopolymer, where the thermoplastic biopolymer is poly- beta -hydroxy butyric acid; and purifying and collecting the produced poly- beta -hydroxy butyric acid. An INDEPENDENT CLAIM is included for a thermoplastic biopolymer production system comprising a sequential batch reactor, a secondary carbon source reactor, and a polymer production reactor.    DESCRIPTION OF DRAWING(S) - The figure shows a functional block diagram of a method for synthesizing thermoplastic biopolymer production system.    Sequential batch reactor (101)    Secondary carbon source reactor (102)    Polymer production reactor. (103)