Enhancement of Crude Oil Biodegradation by Immobilizing of different Bacterial Strains on Porous PVA Hydrogels or Combining of them with their produced Biosurfactants

Abstract

The degradation of the crude oil in wastewater by each of freely microorganisms and by immobilized them on each of crosslinked poly (vinyl alcohol) hydrogel (CPVA) and its foam (CPVAF) was reported. Also, it was studied by using biosurfactants (Bio s ) with free cells. The macroporous CPVAF was prepared by adding CaCO 3 as poreforming agent and epichlorohydrin as crosslinker. The prepared polymers are examining by FTIR, XRD, TGA, DSC and SEM analysis. The microorganisms of B.l., R.e. and P.x. isolated from contaminated effluents were investigated. The ability of these microorganisms to degrade the n-paraffin and PAHs was assessed by GC and HPLC analysis, respectively. Moreover, their stabilities and activities were tested in the growth count of bacteria study. The crosslinked CPVA carrier demonstrated better thermal stability and improvement in the microorganism efficiency with respect to hydrocarbons degradation than these of the CPVAF carrier. Scanning electron microscopy showed the presence of extracellular structures that could play an important role in the immobilization stability of cells on polymers. As well, GC analysis revealed that the percentage biodegradation ability of immobilized cells R.e. on CPVAF for the total n-paraffin was approximately, 100%. While, the HPLC analysis showed that the percentage biodegradation of cells for PAHs was enhancement by immobilized them on CPVA and also, at adding Bio s to them. The results suggest that the potential of using each of CPVA, PVAF as cell carriers and Bio s separately, to free cells to enhancing the biodegradation of petroleum hydrocarbons in an open marine environment.