Decoupling of heat and CO2 release during decomposition of cellulose and its building blocks in soil

作者：Fatemeh Dehghani, Thomas Reitz, Steffen Schlüter, Matthias Kästner, Еvgenia Blagodatskaya · 发表于：Soil Biology and Biochemistry · 年份：2025 · DOI：10.1016/j.soilbio.2025.109801 · 被引用次数：8 · 研究领域：Thermochemical Biomass Conversion Processes、Biofuel production and bioconversion、Electrokinetic Soil Remediation Techniques

The degradation of large biopolymers, such as cellulose, in soil requires several enzymatic hydrolysis steps to produce simpler substrates for microbial uptake. The synthesis of these enzymes requires energy and takes time until they are fully expressed. However, the heat release associated with enzymatic hydrolysis and the temporal delay between this initial heat release and the final carbon mineralization to CO 2 is largely unknown. In this study, we investigated the dynamics of heat and CO 2 release during the sequential decomposition of cellulose to its building blocks, cellobiose and glucose, in soil and related these processes to activities of cellobiohydrolase and β-glucosidase driving the corresponding steps of cellulose decomposition. Moreover, we estimated catabolic heat release during the stepwise enzymatic production of oligo- and monomers in soil by employing fluorogenically labeled substrates. This amounted to the absolute value of 26.5 kJ mol C −1 , approximately 6.5 % of the total combustion enthalpy stored in the applied cellulose. By three complementary approaches, we confirmed that cellobiohydrolase rather than β-glucosidase is the bottleneck step of enzymatic hydrolysis. First, a 36 h temporal decoupling between the heat and CO 2 formation peaks occurred during step-wise enzymatic hydrolysis of cellulose performed by cellobiohydrolase and β-glucosidase towards final mineralization. This decoupling was not observed in the next sequential step of cellobiose ...