Effect of glucose on glycerol metabolism by Clostridium butyricum DSM 5431

Abstract

S . A BB A D-AN D AL OU S SI , J . AM IN E , P . G E RA RD A ND H. P ET IT D EM AN G E. 1998. The levels of 1,3-propanediol dehydrogenase and of the glycerol dehydrogenase in Clostridium butyricum grown on glucose-glycerol mixtures were similar to those found in extracts of cells grown on glycerol alone, which can explain the simultaneous glucose-glycerol consumption. On glycerol, 43% of glycerol was oxidized to organic acids to obtain energy for growth and 57% to produce 1,3-propanediol. With glucose-glycerol mixtures, glucose catabolism was used by the cells to produce energy through the acetate-butyrate production and NADH, whereas glycerol was used chiefly in the utilization of the reducing power since 92-93% of the glycerol flow was converted through the 1,3-propanediol pathway. The apparent K m s for the glycerol dehydrogenase was 16-fold higher for the glycerol than that for the glyceraldehyde in the case of the glyceraldehyde-3-phosphate dehydrogenase and fourfold higher for the NAD + , providing an explanation for the shift of the glycerol flow toward 1,3-propanediol when cells were grown on glucose-glycerol mixtures.

The effect of raw glycerol concentration on the production of 1,3‐propanediol by Clostridium butyricum

“…The constancy of the conversion of glycerol into 1,3-propanediol has been reported for various C butyricum strains, suggesting the presence of mechanisms that precisely partition the carbon flow between biosynthesis of organic acids and formation of 1,3-propanediol. 10,11,13 In contrast, 1,3-propanediol production by Klebsiella pneumoniae DSM 2026 reached 48 g dm −3 with Y PD/S around 0.52 g g −1 only when glycerol was supplied in excess (eg > 50 g dm −3 ) in the culture medium, while significantly lower production was reported at glycerol-limiting conditions. This overproduction of 1,3-propanediol in conditions of excess glycerol was attributed to additional generation of NADH 2 , resulting from pyruvic acid cleavage, a reaction catalyzed by pyruvate dehydrogenase, an enzyme that, in anaerobic conditions, is active only in glycerolexcess conditions.…”

“…This fact can be considered as an expected event, since the pathway of condensation of acetyl-CoA for the biosynthesis of butyric acid is in competition with that of 1,3-propanediol formation as both reactions are related to the re-generation of NADH 2 equivalents, arising from the glycolytic cycle and the phosphoroclastic reaction. 2,3,11 In addition, the theoretical S 0 value that assures the maximum value of PD can be evaluated by putting the first derivative of eqn (4) equal to zero:…”

Comparison of Two Natural 1,3-Propanediol Producers in Regards to the Effect of Glucose Usage as a Co-substrate

“…All of these reports propose co-fermentation as a feasible alternative to improve the 1,3-PDO bioconversion (Abbad-Andaloussi et al, 1998;Ragout et al, 1996;Lüthi-Peng et al, 2002;Biebl and Marten, 1995) resulting in 71% of 1,3-PDO molar yield, which is very close to the theoretical upper limit. This value is significantly better than those obtained without a co-substrate addition (Biebl and Marten, 1995).…”

Enhanced Reducing Equivalent Generation for 1,3-Propanediol Production Through Cofermentation of Glycerol and Xylose by Klebsiella pneumoniae

“…Although the cofermentations of glycerol and other sugars were generally performed [17][18][19], the cosubstrates they used were still pure sugars, which inevitably resulted in high cost of 1,3-PD bio-production. However, xylose was the main carbohydrates derived from the hemicellulosic hydrolysates (HH).…”

“…It is worthy to point out that the residual xylose in medium was relevant to the initial concentration of xylose added in that as more xylose was added, more residual xylose was presented in the medium. Adding sugar as cosubstrate was a feasible way to improve the 1,3-PD conversion and has been widely used [17][18][19]. Although the sugar could not be converted to 1,3-PD, it may be used for cell growth and regeneration of reducing power.…”