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Title: Expression and Characterization of Acidothermus celluloyticus E1 Endoglucanase in Transgenic Duckweed Lemna minor 8627

Journal Article · · Bioresource Technology

Endoglucanase E1 from Acidothermus cellulolyticus was expressed cytosolically under control of the cauliflower mosaic virus 35S promoter in transgenic duckweed, Lemna minor 8627 without any obvious observable phenotypic effects on morphology or rate of growth. The recombinant enzyme co-migrated with the purified catalytic domain fraction of the native E1 protein on western blot analysis, revealing that the cellulose-binding domain was cleaved near or in the linker region. The duckweed-expressed enzyme was biologically active and the expression level was up to 0.24% of total soluble protein. The endoglucanase activity with carboxymethylcellulose averaged 0.2 units mg protein-1 extracted from fresh duckweed. The optimal temperature and pH for E1 enzyme activity were about 80 degrees C and pH 5, respectively. While extraction with HEPES (N-[2-hydroxyethyl]piperazine-N'-[2-ethanesulfonic acid]) buffer (pH 8) resulted in the highest recovery of total soluble proteins and E1 enzyme, extraction with citrate buffer (pH 4.8) at 65 degrees C enriched relative amounts of E1 enzyme in the extract. This study demonstrates that duckweed may offer new options for the expression of cellulolytic enzymes in transgenic plants.

Research Organization:
National Renewable Energy Laboratory (NREL), Golden, CO (United States)
Sponsoring Organization:
USDOE
DOE Contract Number:
AC36-08GO28308
OSTI ID:
944493
Report Number(s):
NREL/JA-270-41767; BIRTEB; MainId:63494; UUID:56bcb3d3-fad4-e411-b769-d89d67132a6d; MainAdminId:45568; TRN: US200902%%798
Journal Information:
Bioresource Technology, Vol. 98, Issue 2007; ISSN 0960-8524
Country of Publication:
United States
Language:
English

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