Reduced catabolic protein expression in Clostridium butyricum DSM 10702 correlate with reduced 1,3-propanediol synthesis at high glycerol loading.
Higher initial glycerol loadings (620 mM) have a negative effect on growth and 1,3-propanediol (1,3-PDO) synthesis in Clostridium butyricum DSM 10702 relative to lower initial glycerol concentrations (170 mM). To help understand metabolic shifts associated with elevated glycerol, protein expression levels were quantified by LC/MS/MS analyses. Thirty one (31) proteins involved in conversion of glycerol to 1,3-PDO and other by-products were analyzed by multiple reaction monitoring (MRM). The analyses revealed that high glycerol concentrations reduced cell growth. The expression levels of most proteins in glycerol catabolism pathways were down-regulated, consistent with the slower growth rates observed. However, at high initial glycerol concentrations, some of the proteins involved in the butyrate synthesis pathways such as a putative ethanol dehydrogenase (CBY_3753) and a 3-hydroxybutyryl-CoA dehydrogenase (CBY_3045) were up-regulated in both exponential and stationary growth phases. Expression levels of proteins (CBY_0500, CBY_0501 and CBY_0502) involved in the reductive pathway of glycerol to 1,3-PDO were consistent with glycerol consumption and product concentrations observed during fermentation at both glycerol concentrations, and the molar yields of 1,3-PDO were similar in both cultures. This is the first report that correlates expression levels of glycerol catabolism enzymes with synthesis of 1,3-PDO in C. butyricum. The results revealed that significant differences in the expression of a small subset of proteins were observed between exponential and stationary growth phases at both low and high glycerol concentrations.
Department of Biosystems Engineering, Faculty of Engineering, University of Manitoba, Manitoba, Winnipeg R3T 5 V6, MB, Canada ; Department of Bioengineering, Ege University, Izmir, Turkey.
Mine
M
Gungormusler-Yilmaz
Manitoba Centre for Proteomics and Systems Biology, University of Manitoba, Winnipeg, Manitoba, Canada.
Dmitry
D
Shamshurin
Manitoba Centre for Proteomics and Systems Biology, University of Manitoba, Winnipeg, Manitoba, Canada.
Marine
M
Grigoryan
Department of Microbiology, University of Manitoba, Winnipeg, Manitoba, Canada.
Marcel
M
Taillefer
Department of Physics and Astronomy, University of Manitoba, Winnipeg, Manitoba, Canada.
Victor
V
Spicer
Department of Physics and Astronomy, University of Manitoba, Winnipeg, Manitoba, Canada.
Oleg V
OV
Krokhin
Department of Microbiology, University of Manitoba, Winnipeg, Manitoba, Canada.
Richard
R
Sparling
Department of Biosystems Engineering, Faculty of Engineering, University of Manitoba, Manitoba, Winnipeg R3T 5 V6, MB, Canada.
David B
DB
Levin
1,3-propanediol synthesis; Clostridium butyricum; Glycerol catabolism; Multiple reaction monitoring; Proteomics