Enhanced Crude Oil Biodegradation in a Two-liquid Phase Partitioning Bioreactor

Z. Z. Ismail and I. A. Abdulrazzak

Abstract
The biodegradation of crude oil at relatively high concentrations in an aquatic environment is constrained by the inherent toxicity of crude oil. In this study, a new application of an aqueous- organic two-liquid phase partitioning bioreactor (TLPPB) was developed to degrade high concentrations of crude oil up to 5000 mg L–1. Silicon oil was selected as the sequestering organic phase to control the delivery of crude oil in aqueous phase by absorbing, and subsequently releasing the crude oil to the microorganisms. The effeciency of the silicon oil- based TLPPB has been compared to the conventional monophasic bioreactor. Regardless of the crude oil concentrations and the type of aqueous phase, complete removal of crude oil up to 100 % was achieved in the two-liquid phase partitioning bioreactor (TLPPB) compared to 75–80 % removal effeciency of crude oil in the monophasic conventional bioreactor. In addition, the performance of TLPPB for crude oil removal was evaluated in terms of the salinity effect using distilled, river, and marine water samples. High salinity of aqueous phase proved to slightly inhibit the microorganisms-bioactivity and hinder the rate of crude oil degradation in the TLPPB. This study indicates the potential of TLPPB for enhancing the transport and biodegradation of crude oil in aqueous solutions.

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Keywords
crude oil, biodegradation, biphasic bioreactor, salinity, silicon oil