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

Moustafa Ymm

doi:10.4172/2157-7463.1000192

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 (Bios) with free cells. The macroporous CPVAF was prepared by adding CaCO3 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 Bios to them. The results suggest that the potential of using each of CPVA, PVAF as cell carriers and Bios separately, to free cells to enhancing the biodegradation of petroleum hydrocarbons in an open marine environment.

Highlights

Biodegradation of petroleum hydrocarbons is a complex process that depends on the nature and the amount of the hydrocarbons present, saturates, aromatics, asphaltenes and the polar compounds [1]
The crosslinked poly (vinyl alcohol) hydrogel (CPVA) carrier had three main degradation steps: the first was at 189 and 260°C and 10% loss weight was ascribed to the release of volatile compounds, mainly water, which were present in the hydrophilic material
For CPVA and crosslinked PVA hydrogel foam (CPVAF), water uptake increases with increase of time, but the swelling property of CPVA is higher than in CPVAF and this was may suggested for occurring a high crosslinking density in CPVAF resulting in lowering the water uptake

Summary

Introduction

Biodegradation of petroleum hydrocarbons is a complex process that depends on the nature and the amount of the hydrocarbons present, saturates, aromatics, asphaltenes and the polar compounds [1]. The polycyclic aromatic hydrocarbons (PAHs) [2] are a minor constituent of crude oils; they are widespread environmental pollutants They are generated from petroleum and many pyrolysis processes. Wide spectra of microbial compounds, including glycolipids, lipopeptides, fatty acids, and polymeric biosurfactants, have been found to have surface activity [9]. They have important advantages, such as biodegradability, low toxicity, and various possible structures, relative to chemically synthesized surfactants [10]. They were use in environmental applications, such as in bioremediation [11] and in enhanced oil recovery [12].

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Conclusion