The Effect of Enzymatic Disintegration Using Cellulase and Lysozyme on the Efficiency of Methane Fermentation of Sewage Sludge

Bartłomiej Macherzyński (), Małgorzata Wszelaka-Rylik (), Anna Marszałek and Elżbieta Popowska-Nowak
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Bartłomiej Macherzyński: Faculty of Biology and Environmental Science, Cardinal Stefan Wyszynski University in Warsaw, Wóycickiego 1/3 Str, 01-938 Warsaw, Poland
Małgorzata Wszelaka-Rylik: Faculty of Biology and Environmental Science, Cardinal Stefan Wyszynski University in Warsaw, Wóycickiego 1/3 Str, 01-938 Warsaw, Poland
Anna Marszałek: Faculty of Environmental and Energy Engineering, Silesian University of Technology, Konarskiego 18 Str, 44-100 Gliwice, Poland
Elżbieta Popowska-Nowak: Faculty of Biology and Environmental Science, Cardinal Stefan Wyszynski University in Warsaw, Wóycickiego 1/3 Str, 01-938 Warsaw, Poland

Energies, 2025, vol. 18, issue 21, 1-15

Abstract: This study presents a novel approach to intensifying the anaerobic digestion of sewage sludge through enzymatic pretreatment using hydrolytic enzymes—cellulase and lysozyme. It aims to determine how enzymatic activation affects the efficiency of methane fermentation, defined as the degree of organic matter decomposition and yield and composition of biogas. An experiment was carried out under mesophilic conditions over 20 days, analyzing the physicochemical properties of sludge, biogas production, methane content, and sanitary parameters. The addition of cellulase and lysozyme significantly enhanced process efficiency, increasing both the rate of organic matter degradation and biogas yield. The highest biogas production values (0.73 L·g −1 d.m. for cellulase and 0.72 L·g −1 d.m. for lysozyme) were obtained at a 4% (w/w) enzyme concentration, with a corresponding increase in the degree of organic matter decomposition to 78.7% and 80.0%, respectively. The produced biogas contained 58–61% methane, exceeding the values observed in the control sample, which indicates a positive effect of enzymatic activation on methane selectivity. Enhanced biogas production was attributed to improved hydrolysis of complex organic compounds, resulting in greater substrate bioavailability for methanogenic microorganisms. Moreover, methane fermentation led to the complete elimination of E. coli from all supernatants, confirming the hygienization potential of the process. The results of this study indicate that enzymatic pretreatment may serve as a viable strategy to improve both the energy efficiency and hygienic safety of anaerobic digestion processes, with relevance for future optimization and full-scale wastewater treatment applications.

Keywords: biogas; methane; sewage sludge; supernatants; anaerobic digestion; E. coli (search for similar items in EconPapers)
JEL-codes: Q Q0 Q4 Q40 Q41 Q42 Q43 Q47 Q48 Q49 (search for similar items in EconPapers)
Date: 2025
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