Py-GC/MS as a Powerful and Rapid Tool for Determining Lignin Compositional and Structural Changes in Biological Processes

Lignin, the second most abundant terrestrial biopolymer, still continues to reveal fascinating complexity within its structural polymeric framework. In this regard, Pyrolysis gas chromatography mass spectrometry (Py-GC/MS) has emerged as a simple, quick and reliable analytical technique for lignin structural analysis. The literature on wide range of applications of Py-GC/MS for lignin analysis is surveyed and subsequent determination of both compositional and structural aspects of lignin polymeric framework are reviewed. The proposed mechanisms of the pyrolytic cleavage of lignin macromolecule with reference to studies of lignin model compounds are also incorporated, herein. By cleaving the complex lignin polymeric framework into characteristic smaller fragments, analytical Py-GC/MS with an extended use of gas chromatography (GC) has evolved to detect the lignin derived molecular fragments. This analytical technique offers unique leverage over other conventional and degradative methods for determining the structural features of lignin in various biological processes such as lignification and the lignin bio-degradation process. This review focuses on the recent developments in the Py-GC/MS analysis of complex lignin macromolecules and reports the characteristic structural changes of the resulting biologically modified lignin.