Ethanol Tolerance in Aspergillus niger and Escherichia coli Phytase


Despite yeast having its own native phytase, the high levels of phytate found in DDGS, a byproduct of ethanol (ETOH) fermentation, suggest that its activity is diminished in the presence of ETOH. Ethanol, a product of grain fermentation, is known to inactivate several hydrolytic enzymes but its effect on phytases is relatively unknown. In this study, two phytases, Aspergillus niger (PhyA) and Escherichia coli (AppA2), were tested for ETOH tolerance. The E. coli phytase displayed greater ethanol tolerance over fungal phytase in the 5% to 10% range. However, ETOH inactivation was found to be reversible for both the enzymes. These differences in ETOH tolerance do suggest that there is a potential to achieve higher ETOH tolerance in phytases by 'structure-function' studies to lower phytic acid levels in DDGS and for other applications.

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E. J. Mullaney, K. Sethumadhavan, S. Boone and A. H. J. Ullah, "Ethanol Tolerance in Aspergillus niger and Escherichia coli Phytase," Advances in Microbiology, Vol. 2 No. 3, 2012, pp. 395-398. doi: 10.4236/aim.2012.23050.

Conflicts of Interest

The authors declare no conflicts of interest.


[1] H. Noureddini, M. Malik, J. Byun and A. J. Ankeny, “Ditribution of Phosphorus Compounds in Corn Processing,” Bioresource Technology, Vol. 100, No. 2, 2009, pp. 731-736. doi:10.1016/j.biortech.2008.05.056
[2] P. Ghosh, N. B. Pamment, and W. R. B. Martin, “Simultaneous Saccharification and Fermentation of Cellulose: β-D-gluodidase Activity and Ethanol Inhibition of Cellulases,” Enzyme and Microbial Technology, Vol. 4, No. 6, 1982, pp. 425-430. doi:10.1016/0141-0229(82)90075-8
[3] Z. Wu and Y. Lee, “Inhibition of the Enzymatic Hydrolysis of Cellulose by Ethanol,” Biotechnology Letters, Vol. 19, No. 10, 1997, pp. 977-979. doi:10.1023/A:1018487015129
[4] P. Kaur, G. Kunze and T. Satyanarayana, “Yeast Phytases: Present Scenario and Future Perspectives,” Critical Reviews in Biotechnology, Vol. 27, No. 2, 2007, pp. 93-109. doi:10.1080/07388550701334519
[5] A. Ullah and D. Gibson, “Extracellular Phytase (E. C. from Aspergillus ficuum NRRL 3135: Purification and Characterization,” Preparative Biochemistry, Vol. 17, No. 1, 1987, pp. 63-91. doi:10.1080/00327488708062477
[6] J. K. Heinonen, and R. J. Lahti, “A New and Convenient Colorimetric Determination of Inorganic Orthophosphate and Its Application to the Assay of Inorganic Pyrophosphatase,” Analytical Biochemistry, Vol. 113, No. 2, 1981, pp. 313-317. doi:10.1016/0003-2697(81)90082-8
[7] T. Kim, E. Mullaney, J. Porres, K. Roneker, S. Crowe, S. Rice, T. Ko, A. Ullah, A, C. Daly, R. Welsh and X. Lei, “Shifting the pH Profile of Aspergillus niger PhyA to Match the Stomach pH Enhances Its Effectiveness as an Animal Feed Additive,” Applied and Environmental Microbiology, Vol. 72, No. 6, 2006, pp. 4397-4403. doi:10.1128/AEM.02612-05
[8] J. Weaver, E. J. Mullaney and Lei, X, “Altering the Substrate Specificity Site of Aspergillus niger PhyB Shifts the pH Optimum to pH 3.2,” Applied Microbiology and Biotechnology, Vol. 76, No. 1, 2008, pp. 117-122. doi:10.1007/s00253-007-0975-z
[9] A. Ullah, K. Sethumadhavan and E. Mullaney, “Salt Effects on the pH Profile and Kinetic Parameters of Micro- bial Phytases,” Journal of Agricultural and Food Chemistry, Vol. 56, No. 9, 2008, pp. 3398-3402. doi:10.1021/jf073137i
[10] J. Szczodrak, and Z. Targonski, “Simultaneous Saccharification and Fermentation of Cellulose: Effect of Ethanol and Cellulases on Particular Stages,” Acta Biotechnology, Vol. 6, No. 6, 1989, pp. 555-564. doi:10.1002/abio.370090613
[11] H. Chen and S. Jin, “Effect of Ethanol and Yeast on Cellulose Activity and Hydrolysis of Crystalline Cellulose,” Enzyme and Microbial Technology, Vol. 39, No. 7, 2006, pp. 1430-1432. doi:10.1016/j.enzmictec.2006.03.027
[12] C. Veit, C. Felby, L. Peckous, L and H. S. Olsen, “Fermentation with a Phytase,” US Patent Application 20020006647, 2001.
[13] J. Shetty, S. Power, D. Ward, B. Paulson and S. Ramer, “Starch Hydrolysis Using Phytase with an Alpha Amylase,” US Patent Application 20080299622, 2007.

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