Continuous succinic acid production by Actinobacillus Succinogenes : suspended cell and biofilm studies in an anaerobic slurry reactor (original) (raw)
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Continuous succinic acid fermentation by Actinobacillus succinogenes in a packed-bed biofilm reactor
Biotechnology for Biofuels, 2018
Background: Succinic acid is one of the most interesting platform chemicals that can be produced in a biorefinery approach. In this study, continuous succinic acid production by Actinobacillus succinogenes fermentation in a packedbed biofilm reactor (PBBR) was investigated. The effects of the operating conditions tested, dilution rate (D), and medium composition (mixture of glucose, xylose, and arabinose-that simulate the composition of a lignocellulosic hydrolysate)-on the PBBR performances were investigated. The maximum succinic acid productivity of 35.0 g L -1 h -1 and the maximum SA concentration were achieved at a D = 1.9 h -1 . The effect of HMF and furfural on succinic acid production was also investigated. HMF resulted to reduce succinic acid production by 22.6%, while furfural caused a reduction of 16% in SA production at the same dilution rate. Conclusion: Succinic acid production by A. succinogenes fermentation in a packed-bed reactor (PBBR) was successfully carried out for more than 5 months. The optimal results were obtained at the dilution rate 0.5 h -1 : 43.0 g L -1 of succinic acid were produced, glucose conversion was 88%; and the volumetric productivity was 22 g L -1 h -1 .
Biochemical Engineering Journal, 2014
Continuous anaerobic fermentations were performed in a novel external-recycle, biofilm reactor using D-glucose and CO 2 as carbon substrates. Succinic acid (SA) yields were found to be an increasing function of glucose consumption with the succinic acid to acetic acid ratio increasing from 2.4 g g-1 at a glucose consumption of 10 g L-1 , to 5.7 g g-1 at a glucose consumption of 50 g L-1. The formic acid to acetic acid ratio decreased from an equimolar value (0.77 g g-1) at a glucose consumption of 10 g L-1 to a value close to zero at 50 g L-1. The highest SA yield on glucose and highest SA titre obtained were 0.91 g g-1 and 48.5 g L-1 respectively. Metabolic flux analysis based on the established C 3 and C 4 metabolic pathways of Actinobacillus succinogenes revealed that the increase in the succinate to acetate ratio could not be attributed to the decrease in formic acid and that an additional source of NADH was present. The fraction of unaccounted NADH increased with glucose consumption, suggesting that additional reducing power is present in the medium or is provided by the activation of an alternative metabolic pathway.
Well Knowledge of the Physiology of Actinobacillus succinogenes to Improve Succinic Acid Production
Applied Microbiology
The anaerobic fermentation of glucose and fructose was performed by Actinobacillus succinogenes 130Z in batch mode using three different volume of bioreactors (0.25, 1 and 3 L). The strategy used was the addition of MgCO3 and fumaric acid (FA) as mineral carbon and the precursor of succinic acid, respectively, in the culture media. Kinetics and yields of succinic acid (SA) production in the presence of sugars in a relevant synthetic medium were investigated. Work on the bench scale (3 L) showed the best results when compared to the small anaerobic reactor’s succinic acid yield and productivity after 96 h of fermentation. For an equal mixture of glucose and fructose used as substrate at 0.4 mol L−1 with the addition of FA as enhancer and under proven optimal conditions (pH 6.8, T = 37 °C, anaerobic condition and 1% v/v of biomass), about 0.5 mol L−1 of SA was obtained, while the theoretical production of succinic acid was 0.74 mol L−1. This concentration corresponded to an experiment...
Applied Microbiology and Biotechnology, 2004
Continuous and repeat-batch biofilm fermentations using Actinobacillus succinogenes were performed with immobilized and suspended-cell systems. For the immobilized continuous system, plastic composite supports (PCS) containing 50% (w/w) polypropylene (PP), 35% (w/w) ground soybean hulls, 5% (w/w) dried bovine albumin, 2.5% (w/w) soybean flour, 2.5% (w/w) yeast extract, 2.5% (w/w) dried red blood cells, and 2.5% (w/w) peptone, or PP tubes (8.5 cm in length) were arranged around the agitator shaft in a grid formation. Agitation was controlled at 125 rpm and 150 rpm. Samples were taken at dilution rates of 0.2, 0.4, 0.6, 0.8, 1.0, and 1.2 h −1 and analyzed for succinic acid production and glucose consumption (g l −1 ). For PCS bioreactors, the highest final succinic acid concentrations (10.1 g −1 , 10.4 g l −1 ) and percentage yields (62.6%, 71.6%) occurred at the dilution rate of 0.2 h −1 . PCS disks were evaluated in a repeat-batch biofilm reactor. Suspended-cell batch fermentations were performed in flasks and a repeat-batch bioreactor. The maximum concentration of succinic acid produced was 40 g l −1 . Peak succinic acid percentage yields in continuous and repeat-batch fermentations of A. succinogenes were observed in suspended-cell continuous fermentations at a dilution rate of 1.0 h −1 (76.2%) and in PCS repeatbatch fermentations with an initial glucose concentration of 40 g l −1 (86.7%).
Succinic Acid Production with Actinobacillus succinogenes ZT-130 in the Presence of Succinic Acid
Current Microbiology, 2010
Glucose fermentation with Actinobacillus succinogenes was carried out at different initial concentrations of succinic acid (SA 0 ) to determine its effect on growth and on the production of succinic acid itself. The specific rates of biomass production, succinic, formic and acetic acids decreased with SA 0 (0-40 g/l). The partially dissociated form of succinic acid had a higher effect on cell growth and production of succinic acid as compared to the non-dissociated forms of the acids, a fact that has not been reported until now. Cell growth fitted the Jerusalimski model, and the Aiba-Shoda model was suitable for quantification of the inhibition for the production of succinic acid. The growth inhibition constants K is and K ip and their summatory were consistent with the experimental values obtained, i.e., 22 g/l for the produced acids and 38 g/l for total acids that were the limits at which the biomass formation ceased.
Kinetic study of succinic acid production by Actinobacillus succinogenes ZT-130
Process Biochemistry, 2008
2.1. Culture strain A. succinogenes ZT-130 ATCC 55617 was used in this study. This microorganism was cultivated weekly in vials using trypticasein soy broth (Difco). 2.2. Cultivation The inoculum (80 ml, trypticasein soy broth sterile medium) was bubbled with CO 2 , incubated at 37 8C for 12 h and then transferred to a bioreactor (inoculum 10%, v/v). The formulation of the growth medium was 10 g/l yeast extract, 10 g/l of NaHCO 3 , 1 g/l of NaCl, 0.05 g/l of MgSO 4 , 6.8 g/l of K 2 HPO 4 , and 15.5 g/l of NaH 2 PO 4. All experiments were performed under the same conditions of pH, temperature, etc. The initial concentration of glucose in the growth medium was varied between 10 and 100 g/l. Fermentation was carried out in a glass bioreactor with a total volume of 1.2 l and initially containing 800 ml of growth medium. During the whole fermentation process, pH was controlled to 6.7 adding a solution of 2.5 M Na 2 CO 3. Temperature was maintained at 37 8C. The fermentation setup was agitated at 300 rpm and CO 2 gas was supplied at a flow rate of 0.4 vvm, for 12 h. After this time the CO 2 needed was supplied by a solution of 2.5 M Na 2 CO 3. 2.3. Analytical methods 2.3.1. Estimation of biomass concentration Biomass was quantified in terms of dry weight; the samples were centrifuged at 10,000 rpm for 15 min, afterwhich they were washed twice with distilled water and dried to a constant weight at 80 8C for 24 h.
Applied microbiology and biotechnology, 2014
Continuous anaerobic fermentations were performed in a biofilm reactor packed with Poraver® beads. Dilution rates (D) varied between 0.054 and 0.72 h(-1), and D-glucose and CO2 gas were used as carbon substrates. Steady-state conditions were shown to be repeatable and independent of the operational history. Production stability was achieved over periods exceeding 80 h at values of D below 0.32 h(-1). In these situations, steady-state variation (expressed as fluctuations in NaOH neutralisation flow rates) exhibited a standard deviation of less than 5 % while no indication of biofilm deactivation was detected. The total biomass amount was found to be independent of the dilution rate with an average dry concentration of 23.8 ± 2.9 g L(-1) obtained for all runs. This suggests that the attachment area controls the extent of biofilm accumulation. Specific succinic acid (SA) productivities, based on the total biomass amount, exhibited a substantial decrease with decreasing D. An SA volumet...
Succinic Acid Production from Hexoses and Pentoses by Fermentation of Actinobacillus Succinogenes
Chemical Engineering Transactions, 2016
Succinic acid is a precursor for many chemicals in the food, pharmaceutical, cosmetic, and biodegradable plastics industries. Nowadays, the biotechnological route to produce succinic acid is focused on processes based on the fermentation of natural materials characterized by high fraction of carbohydrates. Actinobacillus succinogenes is proposed in the literature as a promising strain for the production of succinic acid. Indeed, A. succinogenes may utilize a wide spectrum of carbohydrates as carbon sources. Moreover, the CO2 required for the fermentation allows to include the biotechnological route among the carbon capture and conversion processes. A key issue of fermentation processes aimed at producing succinic acid is the feedstock cost. Pre-requisites of the feedstock are: availability at high mass flow rate over all the year, and non-competitive with (human and animal) food. Lignocellulosic biomass is a potential feedstock because it fulfils the listed pre-requisites. This cont...
2016
Un ni iv ve er rs si it ty y o of f P Pr re et to or ri ia a this study was 22,57 g•L-1 when only YE was used as the nitrogen source in the growth medium, and the highest SA productivity obtained in this study was 1,58 g•L-1 •h-1 when a combination of YE and CSL was used as a nitrogen source. The highest mass ratio of SA to AA achieved was 8,3 g•g-1 when CSL © © U Un ni iv ve er rs si it ty y o of f P Pr re et to or ri ia a was the sole nitrogen source. The mass ratio of FA to AA was consistently less than 0,77 g•g-1 , approaching 0 g•g-1 , as the CSL concentration in the nitrogen source increased. It is assumed that surplus nicotinamide adenine dinucleotide (NADH) is required to achieve the results obtained in this study and it is likely to be provided by the activation or enhancement of an alternative metabolic pathway, i.e. the pentose phosphate pathway, in the presence of CSL or the absence of YE.