Expression of Solvent-Forming Enzymes and Onset of Solvent Production in Batch Cultures of Clostridium beijerinckii (“ Clostridium butylicum ”)

Abstract

Clostridium beijerinckii ("Clostridium butylicum") NRRL B592 and NRRL B593 were grown in batch cultures without pH control. The use of more sensitive and accurate procedures for the determination of solvents in cultures led to the recognition of the onset of solvent production about 2 h earlier than the previously assigned point and at a higher culture pH for both strains. Reliable assays for solvent-forming enzyme activities in cell extracts have also been developed. The results showed that activities of solvent-forming enzymes in strain NRRL B592 started to increase about 1 h before the measured onset of solvent production and that the increase in activities of solvent-forming enzymes was not simultaneous. The degree of increase of these enzyme activities for both strains ranged from 2to 165-fold, with acetoacetate decarboxylase and butanol-isopropanol dehydrogenase showing the largest activity increases. However, the pattern of increase of enzyme activities differed significantly in the two strains of C. beijerinckii. When an increase in solvent-forming enzyme activities was first detected in strain NRRL B592, the culture pH was at 5.7 and the concentrations of total acetic and butyric acids were 5.2 and 3.6 mM, respectively. For strain NRRL B593, the corresponding pH was 5.5. Thus, the culture conditions immediately preceding the expression of solvent-forming enzyme activities differed significantly from those that have been correlated with the production of solvents at later stages of growth.

Coenzyme A-acylating aldehyde dehydrogenase from Clostridium beijerinckii NRRL B592

“…In our study of the expression of solvent-forming enzymes in C. beijerinckii NRRL B592, the CoA-acylating ALDH was found to be a regulated enzyme (37). The activity level of ALDH increased 25-fold, whereas that of alcohol dehydrogenase increased 5-fold, during the switch from acid production to solvent production.…”

“…C. beijerinckii ("C. butylicum") NRRL B592 (VPI 13436) was used in this study. Growth conditions were as described previously (37), except that cells were harvested when the A550 reached 7. Cell paste was stored in liquid nitrogen.…”

“…Aldehyde dehydrogenase (ALDH) activity is present in both eucaryotes and procaryotes, and several forms of ALDH have been found in different cellular locations of mammalian tissues (13,33) or in bacterial cells grown under different conditions (17). ALDHs may be distinguished on the basis of their coenzyme requirements: (i) the coenzyme A (CoA)-independent, NAD(P)+-linked ALDH, which is present in animals, plants, yeasts, and bacteria (14,24,30,31,33); (ii) the CoAand NAD(P)+-independent ALDH, which is present in some bacteria (21,23,25); and (iii) the CoA-acylating, NAD(P)+-linked ALDH, which has been found in several bacteria (3,4,12,18,22,26,28,37), a green alga (19), and a fish (10).…”

Hydrogen Production with Immobilized Sewage Sludge in Three-Phase Fluidized-Bed Bioreactors

“…The profile of hydrogen production rate tended to follow the trend of butyric acid formation (Figure 4), suggesting that the primary hydrogen producers in the culture were HBu‐producing bacteria. As the acid products dominated the soluble metabolites and the production of solvents (e.g., ethanol) was insignificant, the production of H 2 in the culture was metabolically favorable (Yan et al, 1988).…”

Effect of Acetate on Molecular and Physiological Aspects of Clostridium beijerinckii NCIMB 8052 Solvent Production and Strain Degeneration

“…As growth slows, these microorganisms reassimilate acids and produce acetone, butanol, and a small amount of ethanol. The shift to solvent production is associated with induction of solventogenic enzymes and a decrease in the activity of acidogenic enzymes (5,11,35). However, the signals triggering the metabolic shift remain elusive.…”