Continuous succinic acid production by Actinobacillus succinogenes on xylose‑enriched hydrolysate

Show simple item record Bradfield, M.F.A. (Michael Ford Alexander) Mohagheghi, Ali Salvachua, Davinia Smith, Holly Black, Brenna A. Dowe, Nancy Beckham, Gregg T. Nicol, Willie 2016-02-29T05:36:37Z 2016-02-29T05:36:37Z 2015-11-14
dc.description.abstract BACKGROUND : Bio-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. RESULTS : Actinobacillus 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. CONCLUSIONS : The 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. en_ZA
dc.description.librarian am2015 en_ZA
dc.description.sponsorship The National Research Foundation (NRF) and the US Department of Energy Bioenergy Technologies Office. en_ZA
dc.description.uri en_ZA
dc.identifier.citation Bradfield,MFA, Mohagheghi, A, Salvachua, D, Smith, H, Black, BA, Dowe, N, Beckham, GT & Nicol, W, 2015, 'Continuous succinic acid production by actinobacillus succinogenes on xylose‑enriched hydrolysate', Biotechnology for Biofuels, vol. 8, art. no. 181, pp. 1-17. en_ZA
dc.identifier.issn 1754-6834
dc.identifier.other 10.1186/s13068-015-0363-3
dc.language.iso en en_ZA
dc.publisher BioMed Central en_ZA
dc.rights © 2015 Bradfield et al. This article is distributed under the terms of the Creative Commons Attribution 4.0 International License. en_ZA
dc.subject Biorefinery en_ZA
dc.subject Actinobacillus succinogenes en_ZA
dc.subject Succinic acid en_ZA
dc.subject Continuous fermentation en_ZA
dc.subject Corn stover hydrolysate en_ZA
dc.title Continuous succinic acid production by Actinobacillus succinogenes on xylose‑enriched hydrolysate en_ZA
dc.type Article en_ZA

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