Continuous Production Of Succinic Acid Research Articles

Experimental and computational study of a packed-bed bioreactor for the continuous production of succinic acid

In this work we present a packed-bed bioreactor system packed, with immobilised cells in sodium alginate beads, for the biological conversion of glycerol to succinic acid.

Continuous production of succinic acid from glycerol: A complete experimental and computational study

In this work, a bioprocess for the fermentation of A. succinogenes for the production of succinic acid from glycerol was developed, employing a continuous bioreactor with recycle. Moreover, a new bioprocess model was constructed, based on an existing double substrate limitation model, which was validated with experimental results for a range of operating parameters. The model was used to successfully predict the dynamics of the continuous fermentation process and was subsequently employed in optimisation studies to compute the optimal conditions, dilution rate, reflux rate and feed glycerol concentration, that maximise the productivity of bio-succinic acid. In addition, a Pareto front for optimal volumetric productivity and glycerol conversion combinations was computed. Maximum volumetric productivity of 0.518 g/L/h, was achieved at the optimal computed conditions, which were experimentally validated. This is the highest bio-succinic acid productivity reported so far, for such a continuous bioprocess.

Continuous succinic acid production from corn fiber hydrolysate by immobilized Actinobacillus succinogenes in a hollow fiber membrane packed‑bed biofilm reactor

Succinic acid is one of the most useful intermediate chemicals that can be produced in a biorefinery approach. In this study, Actinobacillus succinogenes was immobilized to produce succinic acid using non-detoxified corn fiber hydrolysate (CFH) and a control mimicking the sugars in CFH. Tests were carried out in a hollow fiber membrane packed-bed biofilm reactor (HFM–PBR) operated in a continuous mode. Under steady-state conditions, the bioconversion process was characterized in terms of sugar consumption, succinic acid and other organic acid production. Steady states were obtained at dilution rates of 0.025, 0.05, 0.075, 0.1, 0.2, and 0.3 h−1. The optimal results were achieved at the dilution rate of 0.05 h−1 and recirculation rate of 50 ml/min with a maximum succinic acid concentration, yield and productivity of 31.1 g/L, 0.61 g/g and 1.56 g/L h, respectively, when control was used. Succinic acid concentration, yield and productivity of 23.4 g/L, 0.51 g/g and 1.17 g/L h, respectively, were obtained when CFH was used. Productivity in the HFM–PBR was between 1.3 and 1.9 times higher than productivities for succinic acid production from CFH stated in the literature. The results demonstrated that immobilized A. succinogenes has the potential for effective conversion of an inexpensive biomass feedstock to succinic acid. Furthermore, the process has the potential to serve as a means for value-added chemical biomanufacturing in an integrated corn biorefinery.

Continuous succinic acid production by immobilized cells of Actinobacillus succinogenes in a fluidized bed reactor: Entrapment in alginate beads

The production of succinic acid (SA) was investigated by using immobilized cultures of Actinobacillus succinogenes in alginate beads. Immobilized cell cultures operated in batch mode were tested by varying the initial glucose concentration between 20 and 80 g/L and the bead concentration (mass of beads per liter of fermentation broth) between 50 and 250 g/L. Free cells fermentation tests were also carried out to compare the performances of free cells vs. immobilized cells. The best results were obtained with immobilized cells at initial glucose concentration of 60 g/L and 250 g/L of beads: the final SA concentration was 69 ± 0.2 g/L and the SA yield was 1.15 ± 0.02 g/g.Repeated batch fermentation tests were performed to assess the mechanical stability of the alginate beads.The continuous fermentation process was investigated in a three-phase fluidized bed reactor (FBR) using cell entrapped in alginate beads (the solid phase). The process performances were studied and described as acid production (succinic acid included) and sugar conversion. The performances of the FBR were particularly attractive because it was possible to combine high SA productivity (35.6 g/Lh) with high SA concentration (31 g/L) and substrate conversion (76.4 %).

Continuous succinic acid fermentation by Actinobacillus succinogenes in a packed-bed biofilm reactor

BackgroundSuccinic 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 packed-bed biofilm reactor (PBBR) was investigated.ResultsThe 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.ConclusionSuccinic 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.

Continuous production of succinic acid by fermentation of Actinobacillus succinogenes

Continuous production of succinic acid by fermentation of Actinobacillus succinogenes

Continuous succinic acid production from xylose by Actinobacillus succinogenes.

Continuous, anaerobic fermentations of D-xylose were performed by Actinobacillus succinogenes 130Z in a custom, biofilm reactor at dilution rates of 0.05, 0.10 and 0.30 h(-1). Succinic acid yields on xylose (0.55-0.68 g g(-1)), titres (10.9-29.4 g L(-1)) and productivities (1.5-3.4 g L(-1) h(-1)) were lower than those of a previous study on glucose, but product ratios (succinic acid/acetic acid = 3.0-5.0 g g(-1)) and carbohydrate consumption rates were similar. Also, mass balance closures on xylose were up to 18.2 % lower than those on glucose. A modified HPLC method revealed pyruvic acid excretion at appreciable concentrations (1.2-1.9 g L(-1)) which improved the mass balance closure by up to 16.8 %. Furthermore, redox balances based on the accounted xylose consumed and the excreted metabolites, indicated an overproduction of reducing power. The oxidative pentose phosphate pathway was shown to be a plausible source of the additional reducing power.

Continuous succinic acid production by Actinobacillus succinogenes on xylose-enriched hydrolysate.

BackgroundBio-manufacturing of high-value chemicals in parallel to renewable biofuels has the potential to dramatically improve the overall economic landscape of integrated lignocellulosic biorefineries. However, this will require the generation of carbohydrate streams from lignocellulose in a form suitable for efficient microbial conversion and downstream processing appropriate to the desired end use, making overall process development, along with selection of appropriate target molecules, crucial to the integrated biorefinery. Succinic acid (SA), a high-value target molecule, can be biologically produced from sugars and has the potential to serve as a platform chemical for various chemical and polymer applications. However, the feasibility of microbial SA production at industrially relevant productivities and yields from lignocellulosic biorefinery streams has not yet been reported.ResultsActinobacillus succinogenes 130Z was immobilised in a custom continuous fermentation setup to produce SA on the xylose-enriched fraction of a non-detoxified, xylose-rich corn stover hydrolysate stream produced from deacetylation and dilute acid pretreatment. Effective biofilm attachment, which serves as a natural cell retention strategy to increase cell densities, productivities and resistance to toxicity, was accomplished by means of a novel agitator fitting. A maximum SA titre, yield and productivity of 39.6 g L−1, 0.78 g g−1 and 1.77 g L−1 h−1 were achieved, respectively. Steady states were obtained at dilution rates of 0.02, 0.03, 0.04, and 0.05 h−1 and the stirred biofilm reactor was stable over prolonged periods of operation with a combined fermentation time of 1550 h. Furthermore, it was found that a gradual increase in the dilution rate was required to facilitate adaptation of the culture to the hydrolysate, suggesting a strong evolutionary response to the toxic compounds in the hydrolysate. Moreover, the two primary suspected fermentation inhibitors, furfural and HMF, were metabolised during fermentation with the concentration of each remaining at zero across all steady states.ConclusionsThe results demonstrate that immobilised A. succinogenes has the potential for effective conversion of an industrially relevant, biomass-derived feed stream to succinic acid. Furthermore, due to the attractive yields, productivities and titres achieved in this study, the process has the potential to serve as a means for value-added chemical manufacturing in the integrated biorefinery.

Fermentation process for continuous production of succinic acid in a fibrous bed bioreactor

Succinic acid (SA) was produced from Actinobacillus succinogenes with high cell density by continuous fermentation using fibrous bed bioreactor (FBB). The effects of feeding glucose concentration, dilution rate, and pH on continuous production of SA were examined to achieve an efficient and economical bioprocess. The optimum feeding glucose concentration, dilution rate, and pH were 80g/L, 0.051/h, and 6.0–6.5, respectively. A SA concentration of 55.3±0.8g/L, productivity of 2.77±0.04g/L/h, and yield of 0.8±0.02g/g were obtained, and the continuous fermentation exhibited long-term stability for as long as 18 days (440h) with no obvious fluctuations in both SA and biomass levels. The Jerusalimsky equation for the specific rate of SA production presented the inhibition phenomenon of the product, demonstrating that 60g/L SA might be a critical concentration in this continuous FBB system. The results obtained could be beneficial for future fermentor designs and improvements in SA production.

Continuous succinic acid production by Actinobacillus succinogenes in a biofilm reactor: Steady-state metabolic flux variation

Continuous anaerobic fermentations were performed in a novel external-recycle, biofilm reactor using d-glucose and CO2 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 2.4gg−1 at a glucose consumption of 10gL−1, to 5.7gg−1 at a glucose consumption of 50gL−1. The formic acid to acetic acid ratio decreased from an equimolar value (0.77gg−1) at a glucose consumption of 10gL−1 to a value close to zero at 50gL−1. The highest SA yield on glucose and highest SA titre obtained were 0.91gg−1 and 48.5gL−1 respectively. Metabolic flux analysis based on the established C3 and C4 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.

Continuous Production of Succinic Acid Using an External Membrane Cell Recycle System

Succinic acid was produced by continuous fermentation of Actinobacillus succinogenes sp. 130Z in an external membrane cell recycle reactor to improve viable cell concentration and productivity. Using this system, cell concentration increased to 16.4 g/l at the dilution rate 0.2 h-1, up to 3 times higher than that of batch culture, and the volumetric productivity of succinic acid increased up to 6.63 g/l/h at the dilution rate 0.5 h-1, 5 times higher than that of batch fermentation. However, in the continuous culture using a high dilution rate, operational problems including severe membrane fouling and contamination by lactic acid producer were observed. Another succinic acid producer, Mannheimia succiniciproducens MBEL55E, was also utilized in this system, and the cell concentration and productivity of succinic acid at the dilution rate of 0.3 h-1 were found to be above 3 and 2.3 times higher, respectively, compared with those obtained at the dilution rate of 0.1 h-1. These observations give a deep insight into the process design for a continuous succinic acid production by microorganisms.

Continuous Production of Succinic Acid Using an External Membrane Cell Recycle System

Continuous Production of Succinic Acid Using an External Membrane Cell Recycle System

A new process for the continuous production of succinic acid from glucose at high yield, titer, and productivity

A novel three stages continuous fermentation process for the bioproduction of succinic acid at high concentration, productivity and yield using A. succiniciproducens was developed. This process combined an integrated membrane-bioreactor-electrodialysis system. An energetic characterization of A. succiniciproducens during anaerobic cultured in a cell recycle bioreactor was done first. The very low value of Y(ATP) obtained suggests that an ATP dependent mechanism of succinate export is present in A. succiniciproducens. Under the best culture conditions, biomass concentration and succinate volumetric productivity reach values of 42 g/L and 14.8 g/L.h. These values are respectively 28 and 20 times higher compared to batch cultures done in our laboratory. To limit end-products inhibition on growth, a mono-polar electrodialysis pilot was secondly coupled to the cell recycle bioreactor. This system allowed to continuously remove succinate and acetate from the permeate and recycle an organic acids depleted solution in the reactor. The integrated membrane-bioreactor-electrodialysis process produced a five times concentrated succinate solution (83 g/L) compared to the cell recycle reactor system, at a high average succinate yield of 1.35 mol/mol and a slightly lower volumetric productivity of 10.4 g/L.h. The process combined maximal production yield to high productivity and titer and could be economically viable for the development of a biological route for succinic acid production.

Continuous production of succinic acid by a fumarate-reducing bacterium immobilized in a hollow-fiber bioreactor.

Enterococcus faecalis RKY1, a fumarate-reducing bacterium, was immobilized in an asymmetric hollow-fiber bioreactor (HFBR) for the continuous production of succinic acid. The cells were inoculated into the shell side of the HFBR, which was operated in transverse mode. Since the pH values in the HFBR declined during continuous operation to about 5.7, it was necessary to change the feed pH from 7.0 to 8.0 after 24 h of operation in order to enhance production of succinic acid. During continuous operation with a medium containing fumarate and glycerol, the productivity of succinate was 3.0-10.9 g/(L x h) with an initial concentration of 30 g/L of fumarate, 4.9-14.9 g/(L x h) with 50 g/L of fumarate, and 7.2-17.1 g/(L x h) with 80 g/L of fumarate for dilution rates between 0.1 and 0.4 h(-1). The maximum productivity of succinate obtained by the HFBR (17.1 g of succinate/[L x h]) was 1.7 times higher than that of the batch bioconversions (9.9 g of succinate/ [L x h]) with 80 g/L of fumarate. Furthermore, the long-term stability of the HFBR was demonstrated with a continuously efficient production of succinate for more than 15 d (360 h).