Title: Impact of lignin polymer backbone esters on ionic liquid pretreatment of poplar

Abstract

Biomass pretreatment remains an essential step in lignocellulosic biofuel production, largely to facilitate the efficient removal of lignin and increase enzyme accessibility to the polysaccharides. In recent years, there have been significant efforts in planta to reduce lignin content or modify its composition to overcome the inherent recalcitrance that it imposes on lignocellulosic biomass during processing. Here, transgenic poplar lines in which monolignol ferulate conjugates were synthesized during cell wall development to introduce, during lignification, readily cleavable ester linkages into the lignin polymer backbone (i.e., "zip lignin"), along with wild-type (WT) controls, were pretreated with different ionic liquids (ILs). The strategic introduction of ester bonds into the lignin backbone resulted in increased pretreatment efficiency and released more carbohydrates with lower energy input. After pretreatment with any of three different ILs, and after limited saccharification, the transgenic poplars, especially those with relatively higher amounts of incorporated monolignol ferulate conjugates, yielded up to 23% higher sugar levels compared to WT plants. Our findings clearly demonstrate that the introduction of ester linkages into the lignin polymer backbone decreases biomass recalcitrance in poplar has the potential to reduce the energy and/or amount of IL required for effective pretreatment, and could enable the development ofmore » an economically viable and sustainable biorefinery process.« less

Authors:

Kim, Kwang Ho; Dutta, Tanmoy; Ralph, John; Mansfield, Shawn D.; Simmons, Blake A.; Singh, Seema

Publication Date:

Thu Apr 20 00:00:00 EDT 2017

Research Org.:

Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States)

Sponsoring Org.:

USDOE Office of Science (SC), Biological and Environmental Research (BER)

OSTI Identifier:

1618675

Alternate Identifier(s):

OSTI ID: 1379811

Grant/Contract Number:  

AC02-05CH11231; FC02-07ER64494

Resource Type:

Published Article

Journal Name:

Biotechnology for Biofuels

Additional Journal Information:

Journal Name: Biotechnology for Biofuels Journal Volume: 10 Journal Issue: 1; Journal ID: ISSN 1754-6834

Publisher:

Springer Science + Business Media

Country of Publication:

Netherlands

Language:

English

Subject:

09 BIOMASS FUELS; Biofuels; Biomass; Lignocellulose