Abstract
Polyhydroxyalkanoates (PHAs), which is produced by several bacteria, is a biodegradable polymer that has many industrial and medical applications such as heart valves, scaffold, suture and drug delivery. The aim of the present study is to isolate and identify the bacteria producing polyhydroxybutrate (PHB) from the soil sample of Al-Kharj, south of Riyadh, Kingdom of Saudi Arabia. After staining the bacterial isolates with Nile red stain, the only lighted isolates were selected for further identification. The strongest florescent strain (G-4) was identified by morphological and biochemical tests as Bacillus sp. For further confirmation, PHB was extracted from the G-4 isolate by three different methods of extraction and analyzed by IR. The effect of different conditions on PHB produced by bacterial isolate (G-4) including carbon sources, nitrogen sources, incubation temperatures, pH and incubation periods were studied. The highest production of PHB was observed with cultural media containing 8% of date palm syrup (Khalas) at the pH of 7.2. These results show that Bacillus species identified in soil sample of Al-Kharj produced highest concentration of PHB by using date palm syrup as a carbon source that can substantially reduce substrate and production costs of PHB.