Fungal colonization and enzyme-mediated metabolism of waste coal by Neosartorya fischeri strain ECCN 84

Abstract

Colonization and oxidative metabolism of South African low-rank discard coal by the fungal strain ECCN 84 previously isolated from a coal environment and identified as Neosartorya fischeri was investigated. Results show that waste coal supported fungal growth. Colonization of waste coal particles by N. fischeri ECCN 84 was associated with the formation of compact spherical pellets or sclerotia-like structures. Dissection of the pellets from liquid cultures revealed a nucleus of “engulfed” coal which when analyzed by energy dispersive X-ray spectroscopy showed a time-dependent decline in weight percentage of elemental carbon and an increase in elemental oxygen. Proliferation of peroxisomes in hyphae attached to coal particles and increased extracellular laccase activity occurred after addition of waste coal to cultures of N. fischeri ECCN 84. These results support a role for oxidative enzyme action in the biodegradation of coal and suggest that extracellular laccase is a key component in this process.

Graphical Abstract

Key words:

• Neosartorya fischeri
• coal
• laccase
• biodegradation

Funding

This research was supported by a grant from Anglo American Thermal Coal and the National Research Foundation [IFR1202220169, grant number 80879]. Ms. Lerato M. Sekhohola acknowledges financial support from Anglo American Thermal Coal in the form of a doctoral bursary.

Notes

Abbreviations: ABTS, 2.6-dimethoxyphenol, 2.2′ [azino-bis-(3-ethylbonzthiazoline-6-sulphonic acid) diammonium salt]; EDS, energy dispersive X-ray spectroscopy; LAC, laccase; LiP, lignin peroxidase; MnP, Mn-dependent peroxidase; PBS, phosphate buffered saline; PDA, potato dextrose agar; SEM, scanning electron microscopy.