Affiliation:
1. DOE Great Lakes Bioenergy Research Center, University of Wisconsin—Madison, 3552 Microbial Sciences Building, 1550 Linden Drive, Madison, Wisconsin 53706
Abstract
ABSTRACT
Cellulosic biofuels represent a powerful alternative to petroleum but are currently limited by the inefficiencies of the conversion process. While Gram-positive and fungal organisms have been widely explored as sources of cellulases and hemicellulases for biomass degradation, Gram-negative organisms have received less experimental attention. We investigated the ability of
Cellvibrio japonicus
, a recently sequenced Gram-negative cellulolytic bacterium, to degrade bioenergy-related feedstocks. Using a newly developed biomass medium, we showed that
C. japonicus
is able to utilize corn stover and switchgrass as sole sources of carbon and energy for growth. We also developed tools for directed gene disruptions in
C. japonicus
and used this system to construct a mutant in the
gspD
gene, which is predicted to encode a component of the type II secretion system. The
gspD
::pJGG1 mutant displayed a greater-than-2-fold decrease in endoglucanase secretion compared to wild- type
C. japonicus
. In addition, the mutant strain showed a pronounced growth defect in medium with biomass as a carbon source, yielding 100-fold fewer viable cells than the wild type. To test the potential of
C. japonicus
to undergo metabolic engineering, we constructed a strain able to produce small amounts of ethanol from biomass. Collectively, these data suggest that
C. japonicus
is a useful platform for biomass conversion and biofuel production.
Publisher
American Society for Microbiology
Subject
Ecology,Applied Microbiology and Biotechnology,Food Science,Biotechnology
Cited by
51 articles.
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