Petroleum Sludge as a Feedstock for the Microbial Biodiesel
Production: Emerging Prospects

Abstract
Purpose This study aims to evaluate the possibility of utilizing petroleum sludge as a feedstock for microorganisms synthesizing lipids.
Methods A bio-slurry reactor microcosm experiment simulating a microprototype of petroleum sludge reservoirs in remediation of petroleum contaminated ecosystems was conducted. The microbial lipogenesis relying on a petroleum-based feedstock
and the biodegradation efciency were assessed. The efect of petroleum feedstock on the quantity and major characteristics
of biodiesel precursors was determined.
Results The study demonstrated that the algae-bacteria-yeast consortium had the greatest potential as a biological agent for
biotransformation of petroleum sludge to biodiesel. The optimum period of time for the petroleum hydrocarbons removal and
the synthesis of biodiesel compliant with standard parameters was 90 days. It achieved the lipid content of 58.5%, resulting in
the lipid yield of 15.5 g/L. The lipid productivity of 150.6 mg/L/d was measured up. The key parameters of biofuels obtained
from all microcosms comply with the requirements of the standard EN 14214. The efciency of petroleum hydrocarbons
removal from the microcosm soil was 63%.
Conclusion The capability of the synergistic consortium to produce fatty acids suitable as biodiesel precursors with simultaneous bioremediation of hazardous wastes presents signifcant industrial, ecological and biotechnological interest.

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