Microbial community related to lysozyme digestion process for boosting waste activated sludge biodegradability

• Microbial community shifted obviously affected by lysozyme digestion.
• Similarity among digested communities diminished with the lysozyme dosage augment.
• Community diversity decreased as sludge suffered lysozyme digestion.
• Microbial population distribution tended to be even affected by lysozyme digestion.
• Sludge with high diversity and poor evenness had huge potential to be solubilized.

Waste activated sludge from a lab-scale sequencing batch reactor was used to investigate the potential relation of microbial community with lysozyme digestion process for sludge solubilization. The results showed the microbial community shifted conspicuously as sludge suffered lysozyme digestion. Soluble protein and polysaccharide kept an increasing trend in solution followed with succession of microbial community. The rise of lysozyme dosage augmented the dissimilarity among communities in various digested sludge. A negative relationship presented between community diversity and lysozyme digestion process under various lysozyme/TS from 0 to 240 min (correlation coefficient R2 exceeded 0.9). Pareto–Lorenz curves demonstrated that microbial community tended to be even with sludge disintegration process by lysozyme. Finally, with diversity (H) decrease and community distribution getting even, the SCOD/TCOD increased steadily in solution which suggested the sludge with high community diversity and uneven population distribution might have tremendous potential for improving their biodegradability by lysozyme digestion.