Abstract
The impact of the two adaptation-induced mutations in an improved xylose-fermenting Zymomonas mobilis strain was investigated. The chromosomal mutation at the xylose reductase gene was critical to xylose metabolism by reducing xylitol formation. Together with the plasmid-borne mutation impacting xylose isomerase activity, these two mutations accounted for 80 % of the improvement achieved by adaptation. To generate a strain fermenting xylose in the presence of high acetic acid concentrations, we transferred the two mutations to an acetic acid-tolerant strain. The resulting strain fermented glucose + xylose (each at 5 % w/v) with 1 % (w/v) acetic acid at pH 5.8 to completion with an ethanol yield of 93.4 %, outperforming other reported strains. This work demonstrated the power of applying molecular understanding in strain improvement.
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
References
Agrawal M, Chen RR (2011) Discovery and characterization of a xylose reductase from Zymomonas mobilis ZM4. Biotechnol Lett 33:2127–2133
Agrawal M, Mao Z, Chen RR (2011) Adaptation yields a highly efficient xylose-fermenting Zymomonas mobilis strain. Biotechnol Bioeng 108(4):777–785
Chen RR, Wang Y, Shin H-D, Agrawal M, Mao Z (2009) Improved strains of Zymomonas mobilis for fermentation of biomass. WO Patent WO/2009/132,201
De Graaf AA, Striegel K, Wittig RM, Laufer B, Schmitz G, Wiechert W, Sprenger GA, Sahm H (1999) Metabolic state of Zymomonas mobilis in glucose-, fructose-, and xylose-fed continuous cultures as analysed by C-13- and P-31-NMR spectroscopy. Arch Microbiol 171(6):371–385
Hahn-Hagerdal B, Galbe M, Gorwa-Grauslund MF, Liden G, Zacchi G (2006) Bio-ethanol—the fuel of tomorrow from the residues of today. Trends Biotechnol 24(12):549–556. doi:10.1016/j.tibtech.2006.10.004
Jeon YJ, Svenson CJ, Joachimsthal EL, Rogers PL (2002) Kinetic analysis of ethanol production by an acetate-resistant strain of recombinant Zymomonas mobilis. Biotechnol Lett 24(10):819–824
Joachimsthal E, Haggett KD, Jang JH, Rogers PL (1998) A mutant of Zymomonas mobilis ZM4 capable of ethanol production from glucose in the presence of high acetate concentrations. Biotechnol Lett 20(2):137–142
Joachimsthal E, Haggett KD, Rogers PL (1999) Evaluation of recombinant strains of Zymomonas mobilis for ethanol production from glucose xylose media. Appl Biochem Biotechnol 77–79:147–157
Kim IS, Barrow KD, Rogers PL (2000a) Kinetic and nuclear magnetic resonance studies of xylose metabolism by recombinant Zymomonas mobilis ZM4(pZB5). Appl Environ Microbiol 66(1):186–193
Kim IS, Barrow KD, Rogers PL (2000b) Nuclear magnetic resonance studies of acetic acid inhibition of rec Zymomonas mobilis ZM4(pZB5). Appl Biochem Biotechnol 84–86:357–370
Lawford HG, Rousseau JD, Mohagheghi A, McMillan JD (1999) Fermentation performance characteristics of a prehydrolyzate-adapted xylose-fermenting recombinant Zymomonas in batch and continuous fermentations. Appl Biochem Biotechnol 77–79:191–204
Mohagheghi A, Evans K, Chou YC, Zhang M (2002) Cofermentation of glucose, xylose, and arabinose by genomic DNA-integrated xylose/arabinose fermenting strain of Zymomonas mobilis AX101. Appl Biochem Biotechnol 98:885–898
Rogers PL, Lee KJ, Skotnicki ML, Tribe DE (1982) Ethanol production by Zymomonas mobilis. In: Fiechter A (ed) Microbial reactions, vol 23. Springer, Berlin, pp 37–84
Rogers PL, Jeon YJ, Lee KJ, Lawford HG (2007) Zymomonas mobilis for fuel ethanol and higher value products. Adv Biochem Eng Biotechnol 108:263–288
Viitanen P, McCutchen C, Chou Y, Zhang M (2008) Xylitol synthesis mutant of xylose-utilizing Zymomonas for ethanol production. WO Patent WO/2008/133,638
Viitanen PV, Tao L, Caimi PG, Chou YC, Franden MA, Knoke K, Zhang M, Zhang Y (2011) Zymomonas with improved ethanol production in medium containing concentrated sugars and acetate. US Patent US 7,897,396 B2
Warnecke T, Gill RT (2005) Organic acid toxicity, tolerance, and production in Escherichia coli biorefining applications. Microb Cell Fact 4:25. doi:10.1186/1475-2859-4-25
Zhang M, Eddy C, Deanda K, Finkelstein M, Picataggio S (1995) Metabolic engineering of a pentose metabolism pathway in ethanologenic Zymomonas mobilis. Science 267(5195):240–243
Acknowledgments
We thank Chevron Oil Corp. for funding of this work.
Author information
Authors and Affiliations
Corresponding author
Electronic supplementary material
Below is the link to the electronic supplementary material.
Rights and permissions
About this article
Cite this article
Agrawal, M., Wang, Y. & Chen, R.R. Engineering efficient xylose metabolism into an acetic acid-tolerant Zymomonas mobilis strain by introducing adaptation-induced mutations. Biotechnol Lett 34, 1825–1832 (2012). https://doi.org/10.1007/s10529-012-0970-z
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s10529-012-0970-z