Monitoring of lignin biodegradation using respirometric test and GCxGC-MS

Abstract

Humic substances have an important role in soil fertility, plant three nutrition and the stabilization of soil aggregates. They are divided into three components: humin, humic acids and fulvic acids. In nature, lignocellulose accounts for the major part of biomass and its degradation is one of the main contributors to the formation of humic substances. It is composed of polysaccharides (hemicelluloses and cellulose) and aromatic polymer (lignin). White and brown rot fungi are well known for their essential role in naturally occurring degradation of lignocellulosic biomass, which is enabled by secretion of extracellular ligninolytic enzymes. Composting is an aerobic process during which different waste products are partly mineralized and partly converted to humic substances. It has been claimed that during composting, lignin is the major contributor to the biosynthesis of humic acids. One of the most abundant forms of lignin is Kraft lignin, a byproduct of the alkaline sulfide treatment of lignocelluloses in the paper mill industry. The aim of this work was to investigate the potential of mixed culture of fungi to degrade kraft lignin. Degradation process was monitored with respirometric test to assess the cot production and with comprehensive two-dimensional gas chromatography-mass spectrometry (GCxGC-MS), to identify the degradation products.