In planta expression of A. cellulolyticus Cel5A endocellulase reduces cell wall recalcitrance in tobacco and maize.
The glycoside hydrolase family 5 endocellulase, E1 (Cel5A), from Acidothermus cellulolyticus was transformed into both Nicotiana tabacum and Zea mays with expression targeted to the cell wall under a constitutive promoter. Here we explore the possibility that in planta expression of endocellulases will allow these enzymes to access their substrates during cell wall construction, rendering cellulose more amenable to pretreatment and enzyme digestion. Tobacco and maize plants were healthy and developed normally compared with the wild type (WT). After thermochemical pretreatment and enzyme digestion, transformed plants were clearly more digestible than WT, requiring lower pretreatment severity to achieve comparable conversion levels. Furthermore, the decreased recalcitrance was not due to post-pretreatment residual E1 activity and could not be reproduced by the addition of exogenous E1 to the biomass prior to pretreatment, indicating that the expression of E1 during cell wall construction altered the inherent recalcitrance of the cell wall.
Biosciences Center, National Renewable Energy Laboratory, 1617 Cole Boulevard, MS 3323, Golden, CO 80401, USA. roman.brunecky@nrel.gov.
Roman
R
Brunecky
Michael J
MJ
Selig
Todd B
TB
Vinzant
Michael E
ME
Himmel
David
D
Lee
Michael J
MJ
Blaylock
Stephen R
SR
Decker
Plant Biotechnol J. 2009 Aug;7(6):527-36
19500296
Bioresour Technol. 2005 Dec;96(18):1959-66
16112483
Plant Biotechnol J. 2010 Apr;8(3):332-50
20070870
Appl Biochem Biotechnol. 2004 Spring;113-116:1183-91
15054226
Biotechnol Prog. 1999 Oct 1;15(5):777-793
10514248
Appl Biochem Biotechnol. 2007 Apr;137-140(1-12):207-19
18478390
Transgenic Res. 2007 Dec;16(6):739-49
17237981
Transgenic Res. 2000 Feb;9(1):43-54
10853268
Plant Biotechnol J. 2010 Apr;8(3):308-15
20070871
Bioresour Technol. 2008 Jul;99(11):4997-5005
18006303
Biotechnol Bioeng. 2009 Jun 15;103(3):480-9
19266575
Bioresour Technol. 2005 Apr;96(6):673-86
15588770