Tuesday, May 1, 2012
Napoleon Ballroom C-D, 3rd fl (Sheraton New Orleans)
Clostridium termitidis is an anaerobic, mesophilic bacterium that has the ability to degrade cellulose and hemicellulose to produce sustainable biofuels as fermentation products. No studies exist on the mechanism of cellulose hydrolysis or the catalytic components of C. termitidis. The draft genomic sequence of C. termitidis was screened for cellulolytic/cellulosomal components. Bioinformatics analyses identified 32 major cellulosomal components, with up to 20 components harbouring dockerin domains. The cellular and extracellular proteome of cellulolytic bacteria harbours technologically important enzymes that are needed to degrade cellulose and other bio-molecules. Preliminary studies using 1D MS analysis were carried out to assess the expression of cellulosomal protein in C. termitidis cultured on alpha-cellulose. A total of 27 proteins were identified in stationary phase secretomes and 14 at mid-log phase. There were, however, 7 glycoside hydrolases common to both phases of growth. For pellet samples, 37 cellulosomal proteins were identified at mid-log and 32 at stationary phase, and 30 proteins were common to both samples. Proteomics studies to quantify changes in the relative abundance of glycoside hydrolases and cellulosomal components as a function of carbon source are currently underway using isobaric tags for Relative/Absolute Quantitation (iTRAQ), and subjected to 2D LC/MS/MS analysis. This will provide a systems-level understanding of how C. termitidis adapts to growth on different cellulosic substrates and provide a rational, empirical basis to identify engineering targets for industrial cellulosic fermentation.