Abstract

Polyhydroxyalkanoates (PHAs) are a group of biopolymers resembling plastic due to their physical characteristics. PHAs are known to have great structural variety and biodegradability which add to their importance in replacing synthetic plastics and making them future green materials. Such biopolymers gained worldwide attention. Most bacteria produce biopolymers as an intracellular carbon and energy compounds. Several bacterial strains were isolated from desert soil and tested for the accumulation of PHAs. Off all isolates, only one was shown to have the ability to accumulate significant amounts of PHA.Bacillus spp. which named later as Bacillus SA was isolated and characterized by biochemical and molecular studies using the 16S rRNA. Several concentrations 5.0, 10.0, 15.0, 20.0 and 25.0% (v/v) of date syrup and plastic composite support tubes (PCS) were employed to develop PCS biofilm and motivate PHA accumulation. The stimulation of biofilm formation and production of high PHA accumulation was optimized, and 0.5 g/l urea, 120 rpm agitation and 15% (v/v) date syrup. The cellular dry matter (CDM) was 8.3 g/l with almost 70.5% PHA content. The average molecular weight range was between 3.7 to 4.1x10⁵g/mol. This study demonstrated that a low cost raw material consisting of date syrup can be evaluated as a complex media supplement to meet the nutritional requirements for biopolymer production by suitable isolated bacterial strains. Also, the PCS tube stimulated the biofilm formation and increased the biopolymer accumulation. Consequently, biotechnology production lines of PHA may benefit from this approach to produce low cost PHA using low cost raw material and PCS tubes.

Key word: Date syrup, polyhydroxyalkanoates, plastic composite support (PCS) tube, biofilm, PCS biofilm, suspended cell.