Abstract
Lactic acid was added to batch very high gravity (VHG) fermentations and to continuous VHG fermentations equilibrated to steady state with Saccharomyces cerevisiae. A 53% reduction in colony-forming units (CFU) ml−1 of S. cerevisiae was observed in continuous fermentation at an undissociated lactic acid concentration of 3.44% w/v; and greater than 99.9% reduction was evident at 5.35% w/v lactic acid. The differences in yeast cell number in these fermentations were not due to pH, since batch fermentations over a pH range of 2.5–5.0 did not lead to changes in growth rate. Similar fermentations performed in batch showed that growth inhibition with added lactic acid was nearly identical. This indicates that the apparent high resistance of S. cerevisiae to lactic acid in continuous VHG fermentations is not a function of culture mode. Although the total amount of ethanol decreased from 48.7 g l−1 to 14.5 g l−1 when 4.74% w/v undissociated lactic acid was added, the specific ethanol productivity increased ca. 3.2-fold (from 7.42×10−7 g to 24.0×10−7 g ethanol CFU−1 h−1), which indicated that lactic acid stress improved the ethanol production of each surviving cell. In multistage continuous fermentations, lactic acid was not responsible for the 83% (CFU ml−1) reduction in viable S. cerevisiae yeasts when Lactobacillus paracasei was introduced to the system at a controlled pH of 6.0. The competition for trace nutrients in those fermentations and not lactic acid produced by L. paracasei likely caused the yeast inhibition.
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References
Bayrock DP, Ingledew WM (2001) Application of multistage continuous fermentation for production of fuel alcohol by very-high-gravity fermentation technology. J Ind Microbiol Biotechnol 27:87–93
Bayrock DP, Ingledew WM (2001) Changes in steady state in multistage continuous fuel ethanol fermentation on introduction of a Lactobacillus contaminant. J Ind Microbiol Biotechnol 27:39–45
Cásio F, Leâo C, Uden N van (1987) Transport of lactate and other short-chain monocarboxylates in the yeast Saccharomyces cerevisiae. Appl Environ Microbiol 53:509–513
Capucho I, San Romao MV (1994) Effect of ethanol and fatty acids on malolactic activity of Leuconostoc oenos. Appl Microbiol Biotechnol 42:391–395
Chin PM, Ingledew WM (1994) Effect of lactic acid bacteria on wheat mash fermentations prepared with laboratory backset. Enzyme Microb Technol 16:311–317
Chang IS, Kim BH, Shin PK, Lee WK (1995) Bacterial contamination and its effects on ethanol fermentation. J Microbiol Biotechnol 5:309–314
Connolly C (1999) Bacterial contaminants and their effects on alcohol production. In: Jacques KA, Lyons TP, Kelsall DR (eds) The alcohol textbook: a reference for the beverage, fuel and industrial alcohol industries, 3rd edn. Nottingham University Press, Nottingham, pp 317–334
DeDenken RH (1966) The Crabtree effect: a regulatory system in yeast. J Gen Microbiol 44:149–156
Eklund T (1983) The antimicrobial effect of dissociated and undissociated sorbic acid at different pH levels. J Appl Bacteriol 54:383–389
Ingledew WM (1999) Alcohol production by Saccharomyces cerevisiae: a yeast primer. In: Jacques KA, Lyons TP, Kelsall DR (eds) The alcohol textbook: a reference for the beverage, fuel and industrial alcohol industries, 3rd edn. Nottingham University Press, Nottingham, pp 49–87
Ingledew WM, Burton JD (1980) Membrane filtration: survival of brewing microbes on the membrane during storage at reduced humidities. J Am Soc Brew Chem 38:125–129
Kashket ER (1985) The proton motive force in bacteria: a critical assessment of methods. Annu Rev Microbiol 39:219–242
Maiorella B, Blanch HW, Wilkie CR (1983) By-product inhibition effects on ethanolic fermentation by Saccharomyces cerevisiae. Biotechnol Bioeng 25:103–121
Makanjuola DB, Springham DG (1984) Identification of lactic acid bacteria isolated from different stages of malt and whisky distillery fermentations. J Inst Brew 90:13–19
Narendranath NV, Hynes SH, Thomas KC, Ingledew WM (1997) Effects of lactobacilli on yeast-catalyzed ethanol fermentations. Appl Environ Microbiol 63:4158–4163
Narendranath NV, Thomas KC, Ingledew WM (2000) Effects of acetic acid and lactic acid on the growth of Saccharomyces cerevisiae in a minimal medium. J Ind Microbiol Biotechnol 26:171–177
Narendranath NV, Thomas KC, Ingledew WM (2001) Acetic acid and lactic acid inhibit growth of Saccharomyces cerevisiae by different mechanisms. J Am Soc Brew Chem 59:187–194
Ngang JJE, Letourneau F, Wolniewicz E, Villa P (1990) Inhibition of beet molasses alcoholic fermentation by lactobacilli. Appl Microbiol Biotechnol 33:490–493
Pampulha ME, Loureiro-Dias MC (1989) Combined effect of acetic acid, pH and ethanol on intracellular pH of fermenting yeast. Appl Microbiol Biotechnol 31:547–550
Pertik M, Kappeli O, Fiechter A (1983) An expanded concept for glucose effect in the yeast Saccharomyces uvarum: involvement of short and long-term regulation. J Gen Microbiol 129:43–49
Thomas KC, Hynes SH, Ingledew WM (2002) Influence of medium buffer capacity on inhibition of Saccharomyces cerevisiae growth by acetic and lactic acids. Appl Environ Microbiol 68:1616–1623
Verduyn C, Postma E, Scheffers WA, Dijken JP van (1990) Energetics of Saccharomyces cerevisiae in anaerobic glucose limited chemostat cultures. J Gen Microbiol 136:405–412
Verduyn C, Postma E, Scheffers WA, Dijken JP van (1990) Physiology of Saccharomyces cerevisiae in anaerobic glucose-limited chemostat cultures. J Gen Microbiol 136:395–403
Verduyn C, Postma E, Scheffers WA, Dijken JP van (1992) Effect of benzoic acid on metabolic fluxes in yeasts: a continuous-culture study on the regulation of respiration and alcohol fermentation. Yeast 8:501–517
Zwietering MH, Jongenburger I, Rombouts FM, Riet K van’T (1990) Modeling of the bacterial growth curve. Appl Environ Microbiol 56:1875–1881
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The authors are grateful for financial support from the Canadian Wheat Board, the Natural Sciences and Engineering Research Council, Alltech Inc., the Chippewa Valley Ethanol Co., Corn Plus Corp., and Delta T Corp. The very capable assistance of Mrs. Sandra Hynes and Dr. K.C. Thomas during the course of the project is gratefully acknowledged.
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Bayrock, D.P., Ingledew, W.M. Inhibition of yeast by lactic acid bacteria in continuous culture: nutrient depletion and/or acid toxicity?. J IND MICROBIOL BIOTECHNOL 31, 362–368 (2004). https://doi.org/10.1007/s10295-004-0156-3
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DOI: https://doi.org/10.1007/s10295-004-0156-3