Biopolymer production by some marine bacterial strains isolated from Egypt

Document Type : Original Article


Microbiology Department, Faculty of Agriculture, Cairo University, 12613 Giza, Egypt


PHAs (Polyhydroxyalkanoates) is considered as an energy and carbon reserve that accumulated in bacteria. PHAs are substances converted into CO2 and water within a year by a variety of microbes. Polyhydroxybutyrate (PHB) is the most widely studied PHA. This work was conducted to isolate bacteria that produce PHB from seawater (the new Suez Canal, the city of Qantara, Ismailia, Egypt), screening using Sudan Black B (SBB) and Nile blue A (NbA). A number of twenty isolates stained with SBB gave positive results (black- blue coloring), while sixteen of them were considered as PHB producers when using NbA dye. The strains were identified based on their 16S rRNA gene sequencing and deposited in the GenBank. The temperature and aeration were studied to obtain the high productivity of PHB. The results revealed that the use of 30°C temperature with the use of aeration is more suitable for the production of PHB, where the highest productivity was obtained 2.30 g /l when growing Bacillus megaterium strain YSBM6 at 30°C and shaker speed of 110 rpm for 48 h. FT-IR and GC-MS were used to identify the PHB produced. Results of FTIR and GC-MS analysis confirmed the polymer as PHB and the ability of isolated bacterial strains to produce PHB.


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