Aim and Background. The excessive applications of non-biodegradable polymers, for examples in packaging, disposable utensils and plastic bags of waste materials, have resulted in the environmental accumulation of such polymers. The substitution of these polymers with biodegradable ones seems a promising solution to this problem. 

Materials and Methods. A polyhydroxyalkanoate (PHA) producing bacterium was isolated from environmental samples. This bacterial strain was identified by biochemical and molecular methods using 16s rDNA sequencing. The PHA production by this bacterium was quantified using gas chromatography with an HP-5 column. 

 Results. In this study, the native PHA producing bacterium with most similarity to Bacillus thuringiensis was identified and designated as ZK 86. The optimum condition for PHA production was 37 ºC, pH 7 and aeration at 150 rpm. Under the mentioned condition, the maximum production accounting for 35% of dry cell weight was achieved with glucose as carbon source after 72 h.

Key words. Biodegradable polymer, Bacillus thuringiensis, Polyhydroxylalkanoate. Innate Immunity activated via siRNA.