Anthracene Biodegradation by Oleaginous Rhodococcus opacus for Biodiesel Production and Its Characterization

ABSTRACT

This study examined biodegradation of anthracene, a model low molecular weight polycyclic aromatic hydrocarbon (PAH) by oleaginous Rhodococcus opacus for biodiesel production. Specific biomass growth rate (µ) in the range of 0.0075–0.0185 h⁻¹ could be attained over the initial anthracene concentration (50–500 mg L⁻¹), along with 68–70.6% (w/w) lipid accumulation. 10% (v/v) inoculum size showed more positive effect than 5% (v/v) inoculum size on both anthracene biodegradation efficiency and lipid accumulation by R. opacus. ¹H and ¹³C nuclear magnetic resonance (NMR) spectroscopy of the bacterial lipids revealed 82.25% saturated fatty acids content. Furthermore, the transesterified bacterial lipids predominantly consisted of methyl palmitate (32.4%) and methyl stearate (25.9%) as the major fatty acid methyl esters (FAMEs). Overall, this study revealed a very good potential of the bacterium for the production of biodiesel from PAH-containing wastewater.

KEYWORDS:

• Anthracene
• biodegradation
• biodiesel production
• polycyclic aromatic hydrocarbons
• Rhodococcus opacus

Acknowledgment

The authors thank the Center for the Environment, Indian Institute of Technology Guwahati, for providing the necessary facilities to carry out this research work. The authors also acknowledge Central Instrument Facility (CIF), IIT Guwahati for FESEM, TEM, ¹H and ¹³C NMR analyses.