TY - JOUR
T1 - Expression of the Trichoderma reesei expansin-like protein, swollenin, in poplar results in biomass with improved sugar release by enzymatic hydrolysis
AU - Xiao, Yao
AU - Poovaiah, Charleson
AU - Unda, Faride
AU - Ritchie, Linnea
AU - Dombrov, Maria
AU - Phalen, Caitlin
AU - Argyros, Amy
AU - Coleman, Heather
N1 - Publisher Copyright:
© 2020 Elsevier Ltd
PY - 2020/3
Y1 - 2020/3
N2 - Ethanol production from lignocellulosic biomass has been considered an alternative to corn-based ethanol and fossil fuel. However, the secondary cell wall structure prevents efficient degradation of cellulose. Expression of cell wall degrading enzymes has been suggested as one solution to generate suitable feedstocks for lignocellulosic ethanol production. Swollenin (SWO), originating from Trichoderma reesei, disrupts cellulose structure with low-level hydrolytic activity to the glucan chain. Previously, characterization of T. reesei SWO has been carried out in multiple microorganisms and tobacco. This study heterologously overexpressed T. reesei SWO in hybrid poplar (Populus tremula × alba), a promising feedstock for biofuel production, under the control of either the constitutive Cauliflower Mosaic Virus 35S (CaMV 35S) promoter or the putative vascular tissue specific Subterranean Clover Stunt Virus S7 (SCSV) promoter. Transgenic poplar lines with high or moderate SWO expression level showed abnormal growth and reduced biomass production, along with increased glucose and reduced lignin contents. Increased cellulose crystallinity was observed in two transgenic events. This study also investigated the effect of in planta SWO expression on cellulose saccharification efficiency and found that transgenic events improved glucan conversion rates compared to wild type poplar. The results suggest SWO-overexpressing transgenic poplar lines could be a potential feedstock for ethanol production.
AB - Ethanol production from lignocellulosic biomass has been considered an alternative to corn-based ethanol and fossil fuel. However, the secondary cell wall structure prevents efficient degradation of cellulose. Expression of cell wall degrading enzymes has been suggested as one solution to generate suitable feedstocks for lignocellulosic ethanol production. Swollenin (SWO), originating from Trichoderma reesei, disrupts cellulose structure with low-level hydrolytic activity to the glucan chain. Previously, characterization of T. reesei SWO has been carried out in multiple microorganisms and tobacco. This study heterologously overexpressed T. reesei SWO in hybrid poplar (Populus tremula × alba), a promising feedstock for biofuel production, under the control of either the constitutive Cauliflower Mosaic Virus 35S (CaMV 35S) promoter or the putative vascular tissue specific Subterranean Clover Stunt Virus S7 (SCSV) promoter. Transgenic poplar lines with high or moderate SWO expression level showed abnormal growth and reduced biomass production, along with increased glucose and reduced lignin contents. Increased cellulose crystallinity was observed in two transgenic events. This study also investigated the effect of in planta SWO expression on cellulose saccharification efficiency and found that transgenic events improved glucan conversion rates compared to wild type poplar. The results suggest SWO-overexpressing transgenic poplar lines could be a potential feedstock for ethanol production.
KW - Biofuel production
KW - Non-hydrolytic activity
KW - Saccharification
KW - Transgenic poplar
KW - Trichoderma reesei swollenin
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U2 - 10.1016/j.biombioe.2020.105473
DO - 10.1016/j.biombioe.2020.105473
M3 - Article
AN - SCOPUS:85078439308
SN - 0961-9534
VL - 134
JO - Biomass and Bioenergy
JF - Biomass and Bioenergy
M1 - 105473
ER -