Evaluating the low-rank coal degradation efficiency bioaugmented with activated sludge

Area of Science:

• Environmental Microbiology
• Biotechnology
• Coal Science

Background:

• Low-rank coals (LRC) present utilization challenges.
• Microbial bioaugmentation offers a sustainable approach for LRC valorization.
• Developing effective microbially-based coal degradation techniques is crucial.

Purpose of the Study:

• To investigate the impact of activated sludge (AS) as a microbial supplement for enhancing LRC biodegradation.
• To characterize the biodegradation products of LRC treated with AS.
• To analyze the microbial community shifts during bioaugmentation.

Main Methods:

• Bioaugmentation of LRC with activated sludge (AS).
• Characterization of LRC and biodegradation products using Excitation-Emission Matrices (EEMs) and Fourier-Transform Infrared Spectroscopy (FTIR).
• Analysis of bacterial communities (16S rRNA sequencing) and community-level physiological profiling (CLPP).

Main Results:

• EEMs detected humic-like organic complexes in biodegradation products.
• FTIR analysis revealed an increase in carboxyl groups, indicating aerobic oxidation.
• AS supplementation significantly increased the metabolic activity compared to native coal microbiota, with Actinobacteria and Proteobacteria dominant in coal, and Firmicutes in AS.

Conclusions:

• Activated sludge (AS) effectively stimulates the biodegradation and transformation of low-rank coal (LRC).
• Microbial bioaugmentation with AS is a promising strategy for deriving value-added products from LRC.
• The study demonstrates successful enhancement of LRC utilization through exogenous microbial supplementation.