Synergistic Biotransformation of Low-Rank Coal Into Chemical Feedstocks by Indigenous Fungi and Chemical Pretreatment.

Fungal biotransformation of subbituminous coal into chemical feedstocks provides an eco-friendly and cost-effective approach for sustainable coal utilization. In this study, the fungal isolates AD-3 (Neurospora crassa) and AD-5 (Penicillium simplicissimum) from a Pakistani subbituminous coal, optimization, and enhancing agents play a valuable role in the enhanced biodegradation processes. Optimal conditions yielded substantial organic release with 1% and 1.5% (w/v) glucose, 0.5% pulverized coal within 7 and 17 days of incubation. NaOH and sodium acetate enhanced fungal coal degradation by modifying coal structure and promoting organic compound release. The GC-MS analysis of the solubilized black liquid showed a more diverse variety of organic compounds in chemically treated coal than the virgin coal. The analyses showed 31.29% ± 0.23% (AD-3) and 44.9% ± 0.26% (AD-5) solubilization of virgin coal, increasing to 50.9% ± 0.23% (AD-3) and 68.4% ± 0.30% (AD-5) after chemical pretreatment. The solubilized fraction and residual coal were analyzed with FTIR to explore the functional group aroused by the conjugative effect of the chemical and fungal attacks. This analysis showed that the combination of chemical treatment and biotransformation by indigenous fungi from coal environments has the potential to exploit the low-rank coal for chemical feedstock production.