Compositional Analysis of Lignin in Bioenergy Crops and De-polymerization via Pretreatment

Authors: MANISSERI, CHITHRA - JOINT BIOENERGY INSTITUTE; LI, CHENLIN - JOINT BIOENERGY INSTITUTE; SMITH, ANDREA - JOINT BIOENERGY INSTITUTE; ARORA, ROHIT - JOINT BIOENERGY INSTITUTE; BENKE, PETER - JOINT BIOENERGY INSTITUTE; BHARADWAJ, RAJIV - JOINT BIOENERGY INSTITUTE; ZENDEJAS, FRANK - JOINT BIOENERGY INSTITUTE; SCHELLER, HENRIK - JOINT BIOENERGY INSTITUTE; Vogel, Kenneth; SIMMONS, BLAKE - JOINT BIOENERGY INSTITUTE; SINGH, SEEMA - JOINT BIOENERGY INSTITUTE

Submitted to: Biotechnology for Fuels and Chemicals Symposium Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: 2/27/2009
Publication Date: 5/3/2009
Citation: Manisseri, C., Li, C., Smith, A.M., Arora, R., Benke, P., Bharadwaj, R., Zendejas, F., Scheller, H.V., Vogel, K.P., Simmons, B.A., Singh, S. 2009. Compositional Analysis of Lignin in Bioenergy Crops and De-polymerization via Pretreatment. p. 160. Abstracts 31st Symposium on Biotechnology for Fuels and Chemicals, Soc. for Industrial Microbiology. May 3-6, San Francisco, CA.

Interpretive Summary: Lignin is a complex phenylpropanoid polymer derived from enzyme mediated radical coupling of coniferyl, sinapyl and coumaryl alcohols with main functions to impart strength to plant cell wall, transport water and provide defense against pathogens. Physical, chemical and biological degradation of cellulose and hemicellulose is inversely proportional to the amount of lignification. Lignin therefore confers biomass recalcitrance and necessitates pretreatment steps, which are costly and must be improved if bioenergy from biomass is to be realized. New emerging pretreatement techniques employing ionic liquids have shown great promise and are very effective in breaking inter and intramolecular hydrogen bonding in cellulose microfibrills, thereby making cellulose amorphous and enhancing saccharification in both model cellulose and biomass. However, detailed understanding and insight into the extent of lignin depolymerization during pretreatment processes and the influence of degree of lignification, lignin chemical composition, and chemical association between lignin and hemicellulose are lacking. Towards the goal of gaining molecular level understanding of lignin signatures and their influence on depolymerization via pretreatment, we are utilizing light scattering, spectroscopy, chromatography and modified wet chemistry techniques. We aim to gain knowledge for attaining optimized pretreatment conditions, aiding efforts on altering chemistry in bioenergy crops, and perhaps selective depolymerization of celluloses or lignin. We will present results on our ongoing experiments on potential bioenergy crops with varied degree of lignification and lignin composition characterized before and after pretreatment. In addition, disruption of lignin-hemicellulose association during pretreatment will be discussed.

Technical Abstract: Lignin is a complex phenylpropanoid polymer derived from enzyme mediated radical coupling of coniferyl, sinapyl and coumaryl alcohols with main functions to impart strength to plant cell wall, transport water and provide defense against pathogens. Physical, chemical and biological degradation of cellulose and hemicellulose is inversely proportional to the amount of lignification. Lignin therefore confers biomass recalcitrance and necessitates pretreatment steps, which are costly and must be improved if bioenergy from biomass is to be realized. New emerging pretreatement techniques employing ionic liquids have shown great promise and are very effective in breaking inter and intramolecular hydrogen bonding in cellulose microfibrills, thereby making cellulose amorphous and enhancing saccharification in both model cellulose and biomass. However, detailed understanding and insight into the extent of lignin depolymerization during pretreatment processes and the influence of degree of lignification, lignin chemical composition, and chemical association between lignin and hemicellulose are lacking. Towards the goal of gaining molecular level understanding of lignin signatures and their influence on depolymerization via pretreatment, we are utilizing light scattering, spectroscopy, chromatography and modified wet chemistry techniques. We aim to gain knowledge for attaining optimized pretreatment conditions, aiding efforts on altering chemistry in bioenergy crops, and perhaps selective depolymerization of celluloses or lignin. We will present results on our ongoing experiments on potential bioenergy crops with varied degree of lignification and lignin composition characterized before and after pretreatment. In addition, disruption of lignin-hemicellulose association during pretreatment will be discussed.