Culture fluorescence characteristics and its metabolic significance in batch cultures of Clostridium acetobutylicum

1987 ◽  
Vol 9 (2) ◽  
pp. 139-142 ◽  
Author(s):  
S. P. Srinivas ◽  
R. Mutharasan
Keyword(s):  
Clostridium Acetobutylicum ◽  
Batch Cultures ◽  
Fluorescence Characteristics ◽  
Metabolic Significance

scholarly journals d-2,3-Butanediol Production Due to Heterologous Expression of an Acetoin Reductase in Clostridium acetobutylicum

2011 ◽  
Vol 77 (8) ◽  
pp. 2582-2588 ◽  
Author(s):  
Marco A. J. Siemerink ◽  
Wouter Kuit ◽  
Ana M. López Contreras ◽  
Gerrit Eggink ◽  
John van der Oost ◽  
...  
Keyword(s):  
Experimental Data ◽  
Heterologous Expression ◽  
Metabolic Network ◽  
Clostridium Acetobutylicum ◽  
Clostridium Beijerinckii ◽  
Racemic Mixture ◽  
Gene Encoding ◽  
Content Type ◽  
Batch Cultures

ABSTRACTAcetoin reductase (ACR) catalyzes the conversion of acetoin to 2,3-butanediol. Under certain conditions,Clostridium acetobutylicumATCC 824 (and strains derived from it) generates bothd- andl-stereoisomers of acetoin, but because of the absence of an ACR enzyme, it does not produce 2,3-butanediol. A gene encoding ACR fromClostridium beijerinckiiNCIMB 8052 was functionally expressed inC. acetobutylicumunder the control of two strong promoters, the constitutivethlpromoter and the late exponentialadcpromoter. Both ACR-overproducing strains were grown in batch cultures, during which 89 to 90% of the natively produced acetoin was converted to 20 to 22 mMd-2,3-butanediol. The addition of a racemic mixture of acetoin led to the production of bothd-2,3-butanediol andmeso-2,3-butanediol. A metabolic network that is in agreement with the experimental data is proposed. Native 2,3-butanediol production is a first step toward a potential homofermentative 2-butanol-producing strain ofC. acetobutylicum.

scholarly journals Cap0037, a Novel Global Regulator of Clostridium acetobutylicum Metabolism

mBio ◽  
2016 ◽  
Vol 7 (5) ◽  
Author(s):  
Ngoc-Phuong-Thao Nguyen ◽  
Sonja Linder ◽  
Stefanie K. Flitsch ◽  
Bettina Schiel-Bengelsdorf ◽  
Peter Dürre ◽  
...  
Keyword(s):  
Clostridium Acetobutylicum ◽  
Metabolic Flux ◽  
High Yield ◽  
Ferric Uptake Regulator ◽  
Batch Cultures ◽  
Dna Footprinting ◽  
Chemostat Cultures ◽  
Sense Strand ◽  
Expression Mechanism

ABSTRACT An operon comprising two genes, CA_P0037 and CA_P0036 , that encode proteins of unknown function that were previously shown to be highly expressed in acidogenic cells and repressed in solventogenic and alcohologenic cells is located on the pSOL1 megaplasmid of Clostridium acetobutylicum upstream of adhE2 . A CA_P0037 :: int ( 189/190s ) mutant in which an intron was inserted at position 189/190 in the sense strand of CA_P0037 was successfully generated by the Targetron technique. The resultant mutant showed significantly different metabolic flux patterns in acidogenic (producing mainly lactate, butyrate, and butanol) and alcohologenic (producing mainly butyrate, acetate, and lactate) chemostat cultures but not in solventogenic or batch cultures. Transcriptomic investigation of the CA_P0037 :: int ( 189/190s ) mutant showed that inactivation of CA_P0037 significantly affected the expression of more than 258 genes under acidogenic conditions. Surprisingly, genes belonging to the Fur regulon, involved in iron transport ( CA_C1029-CA_C1032 ), or coding for the main flavodoxin ( CA_C0587 ) were the most significantly expressed genes under all conditions, whereas fur (coding for the ferric uptake regulator) gene expression remained unchanged. Furthermore, most of the genes of the Rex regulon, such as the adhE2 and ldhA genes, and of the PerR regulon, such as rbr3A-rbr3B and dfx , were overexpressed in the mutant. In addition, the whole CA_P0037-CA_P0036 operon was highly expressed under all conditions in the CA_P0037 :: int ( 189/190s ) mutant, suggesting a self-regulated expression mechanism. Cap0037 was shown to bind to the CA_P0037-CA_P0036 operon, sol operon, and adc promoters, and the binding sites were determined by DNA footprinting. Finally, a putative Cap0037 regulon was generated using a bioinformatic approach . IMPORTANCE Clostridium acetobutylicum is well-known for its ability to produce solvents, especially n -butanol. Understanding the regulatory network of C. acetobutylicum will be crucial for further engineering to obtain a strain capable of producing n -butanol at high yield and selectivity. This study has discovered that the Cap0037 protein is a novel regulator of C. acetobutylicum that drastically affects metabolism under both acidogenic and alcohologenic fermentation conditions. This is pioneering work for further determining the regulatory mechanism of Cap0037 in C. acetobutylicum and studying the role of proteins homologous to Cap0037 in other members of the phylum Firmicutes .

0471 The effect of binding feed emzymes to spores of Bacillius subtlis and Bacillius coagulans on in vitro NDF digestibility in ruminal batch cultures

2016 ◽  
Vol 94 (suppl_5) ◽  
pp. 225-225
Author(s):  
C. L. Rosser ◽  
L. Jin ◽  
K. A. Beauchemin ◽  
M. Oba ◽  
S. M. Cutting ◽  
...  
Keyword(s):  
Batch Cultures

The role of a metabolic intermediate in the biodegradation of inhibitory substrates

1997 ◽  
Vol 36 (10) ◽  
pp. 27-36 ◽  
Author(s):  
P. Mungkarndee ◽  
S. M. Rao Bhamidimarri ◽  
A. J. Mawson ◽  
R. Chong
Keyword(s):  
The Other ◽  
Metabolic Product ◽  
Dichlorophenoxyacetic Acid ◽  
Mutual Inhibition ◽  
Metabolic Intermediate ◽  
Batch Cultures ◽  
Ortho Cresol ◽  
2,4 Dichlorophenoxyacetic Acid

Biodegradation of the mixed inhibitory substrates, 2,4-dichlorophenoxyacetic acid (2,4-D) and para-chloro-ortho-cresol (PCOC) was studied in aerobic batch cultures. Each substrate added beyond certain concentrations inhibited the degradation of the other. This mutual inhibition was found to be enhanced by 2,4-dichlorophenol (2,4-DCP) which is an intermediate metabolic product of 2,4-D. When 2,4-DCP accumulated to approximatelY 40 mg/l degradation of all compounds in the mixed 2,4-D and PCOC substrate system was completely inhibited. The degradation of 2,4-D and PCOC individually was also found to be inhibited by elevated concentrations of 2,4-DCP added externally, while PCOC inhibited the utilization of the intermediate.

Activated carbon as a better habitat for water and wastewater treatment microorganisms

2000 ◽  
Vol 42 (12) ◽  
pp. 149-154 ◽  
Author(s):  
M. Okada ◽  
H. Morinaga ◽  
W. Nishijima
Keyword(s):  
Batch Culture ◽  
Bacterial Growth ◽  
Membrane Filter ◽  
Synthetic Medium ◽  
Dialysis Tubing ◽  
Water And Wastewater Treatment ◽  
Batch Cultures ◽  
K 12 ◽  
Bacterial Yield ◽  
Adsorption Desorption

Effects of PAC on bacterial activity were evaluated by sequencing batch cultures (20 hours each) of E.coli K-12 on synthetic medium containing glucose as a sole carbon source. Four suspended sequencing batch culture systems were operated; CP: cultures supplemented with PAC, CR: cultures with removal of metabolites by PAC at the end of each batch culture, CD: cultures supplemented with PAC in dialysis tubing to separate from E.coli, and CC: cultures without PAC (control). The supernatant of each batch culture was filtered through a membrane filter (0.2 μm) and was mixed with the same volume of fresh medium to be used as the medium for the next batch culture. The sequencing batch cultures were repeated three times for all the systems. The bacterial growth in CC was inhibited with the increase in the number of batch cultures. Although a significant amount of metabolites was accumulated in the 3rd batch culture of CC, little accumulation was noted in the 3rd batch culture of CP. No growth inhibition was noted in CP for all the batch cultures. The little differences in the bacterial yield and metabolite accumulation between CR and CD suggested that adsorption/desorption of metabolites with PAC did not play a major role in bacterial growth. PAC addition may partly stimulate the growth by the removal of growth inhibiting metabolites. However, the fact that CP showed higher yield than CR and CD indicated that the contact between bacteria and PAC plays a significant role in the growth of bacteria.

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