Treatability of recombinant T4 bacteriophage lysozyme with secondary sludge

The hydrolysis of secondary sludge is a rate-limiting step in anaerobic digestion for bioenergy production. In this study, recombinant bacteriophage T4 lysozymes were applied as a pretreatment, achieving volatile suspended solids (VSS) removal of 18.1-57.0 %. Moreover, lysozyme application increased the biogasification rate constant by 0.3-1.0 d^-1, irrespective of sludge origin or lysozyme source. A significant positive correlation (p < 0.001) was observed between VSS removal and methane yield. Simplicispira, Dokdonella, and Thermomonas were initially dominant and largely retained their relative abundance in lysozyme-treated secondary sludge. By contrast, in cultivated sludge enriched with 40 g/L glucose, Klebsiella, Kosakonia, and Dysgonomonas exhibited sharp increases after lysozyme addition, reflecting their capacity for rapid growth under hydrolytic conditions. These results demonstrate that bacteriophage-derived lysozymes can effectively enhance hydrolysis and accelerate methane production, highlighting their potential as enzymatic pretreatment agents for improving the efficiency of anaerobic digestion.