Evaluation of the lignite biotransformation capacity of Fusarium sp. NF01 cultured on different growth substrates

Abstract

The screening and studying the lignite solubilization/degradation capacities of indigenous microorganisms are key to exploring the in-situ biotransformation of lignite. Herein, a fungus was isolated from in-situ lignite samples and identified as Fusarium sp. NF01. This isolate was then cultured on four different carbon sources to evaluate its lignite-transformation capacity. When cultured on a solid agar medium containing sodium gluconate or sodium glutamate, Fusarium sp. NF01 completely liquefied 0.5 g of lignite within 6 days, and when cultured in a liquid medium containing sodium gluconate, the weight of lignite decreased by 28.4% within 7 days. Elemental analysis showed that the rate of lignite biodegradation was inversely proportional to the C:O ratio of the residual lignite samples. Additionally, a 5.9% biodesulfurization rate was achieved when Fusarium sp. NF01 was cultured in the presence of sodium gluconate. Finally, Fourier-transform infrared analysis of the residual lignite samples revealed relatively weak signal intensities of the signature peaks representing the following: aromatic ring side chains; ether, ester, and alcohol bonds; aromatic ring carbon–carbon double bonds; and aliphatic methyl and methylene. The results show that Fusarium sp. NF01 degrades lignite in a carbon-dependent manner and could be thus used for the bioconversion of subsurface coalbeds.