Degradation kinetics of lignocellulolytic enzymes in a biogas reactor by quanti-tative mass spectrometry

Supplementation of lignocellulose-degrading enzymes can be used to enhance the performance of biogas production in industrial biogas plants. Since the structural stability of these enzyme prepa-rations is essential for efficient application, reliable methods for the assessment of enzyme stability are crucial. Here, a mass spectrometric-based assay was established to monitor the structural sta-bility of enzymes, i.e. the structural integrity of these proteins, in anaerobic digestion (AD). Analy-sis of extracts of Lentinula edodes revealed rapid degradation of lignocellulose-degrading enzymes with an approximate half-life of 1.5 h. The observed low structural stability of lignocellulose-degrading enzymes in AD corresponded with previous results obtained for biogas content. The established workflow can be easily adapted for the monitoring of other enzyme formulations and provides a platform for evaluating the effect of enzyme additions in AD together with a characterization of the biochemical methane potential used to determine the biodegradability of organic substrates.