Microbial Conversion of Glycerol to 1,3-Propanediol: Physiological Comparison of a Natural Producer, Clostridium butyricum VPI 3266, and an Engineered Strain, Clostridium acetobutylicum DG1(pSPD5)

• DOI: 10.1128/aem.72.1.96-101.2006
• Publication Date: 2006-01-03T20:33:36Z
• Authors: María González-...; Isabelle Meynial-...; Filipa Mendes; Philippe Soucaille; Isabel Vasconcelos
• Keywords: Clostridium butyricum; Clostridium acetobutylicum; Glycerol kinase; 1,3-Propanediol

Clostridium acetobutylicum is not able to grow on glycerol as the sole carbon source since it cannot reoxidize excess of NADH generated by catabolism. Nevertheless, when pSPD5 plasmid, carrying NADH-consuming 1,3-propanediol pathway from C. butyricum VPI 3266, was introduced into DG1, growth achieved, and produced. In order compare physiological behavior recombinant DG1(pSPD5) strain with that natural producer both strains were grown in chemostat cultures source. The same "global behavior" observed for strains: main fermentation product, qH2 flux very low. However, looking at key intracellular enzyme levels, significant differences observed. Firstly, oxidation different: uses a dehydrogenase dihydroxyacetone kinase, while kinase glycerol-3-phosphate dehydrogenase. Secondly, electron flow differentially regulated: (i) vitro hydrogenase activity 10-fold lower than DG1(pSPD5), (ii) ferredoxin-NAD+ reductase high NADH-ferredoxin low reverse 3266. Thirdly, lactate only detected culture, explaining why this microorganism produces lactate.