Saccharomyces cerevisiae lactic acid

Saccharomyces cerevisiae Lactic acid production A muscle bovine lactate dehydrogenase gene (LDH-A) was expressed in S. cerevisiae, a nd lactic acid was produced in titers of 20 g/liter with productivities of 11 g/liter/h due to the acid tolerance of S. cerevisiae this organism may serve as an alternative for substitution of bacteria for lactic acid prxrduction 108... 

Simple organic molecules Ethanol Butanol Acetone Acetic acid Lactic acid Saccharomyces cerevisiae Pachysolen tamiophilus, some Clostridium spp. Clostridium acetobutylicum, C. saccharoacetobutylicum Clostridium acetobutylicum, C. saccharoacetobutylicum Various acetic acid bacteria Lactobacillus spp. 

On-line MIR ZnSe ATR analysis of microbial cultures has been used primarily for non-invasive monitoring of alcoholic or lactic fermentations. Alberti et al. [76] reported the use of a ZnSe cylindrical ATR crystal to monitor accurately substrate and product concentrations from a fed-batch fermentation of Saccharomyces cerevisiae. Picque et al. [77] also used a ZnSe ATR cell for monitoring fermentations and found that whereas NIR spectra obtained from alcoholic or lactic fermentation samples contained no peaks or zones whose absorbance varied significantly, both transmission and ATR MIR could be used successfully to measure products. Fayolle et al. [78] have employed MIR for online analysis of substrate, major metabolites and lactic acid bacteria in a fermentation process (using a germanium window flow-through cell), and... 

Fig. 3 Metabolic engineering for L-lactic acid production in Saccharomyces cerevisiae. The abbreviation of enzymes is described as follows LDH bovine lactate dehydrogenase, PDC pyruvate decarboxylase complex encoded by the genes PDC1, PDC5, and PDC6, which were deleted in this strategy...

FCB2 from Saccharomyces cerevisiae catalyzes the oxidation of lactic acid to pyruvic acid with subsequent transfer of two electrons to cytochrome c (Lederer, 1991). The enzyme is located in the intermembrane space of yeast mitochondria and is part of an independent branch of the... 

Lemaresquier, H. (1987). Inter-relationship between strains of Saccharomyces cerevisiae from Champagne area and lactic acid bacteria. Lett. App. Microbiol, 4, 91-94. 

Valli, M., Sauer, M., Branduardi, P., Borth, N., Porro, D., and Mattanovich, D. 2006. Improvement of lactic acid production in Saccharomyces cerevisiae by cell sorting for high intracellular pH. Applied and Environmental Microbiology 72 5492-5499. 

In 2006 Saccharomyces cerevisiae was found for the first time to be able to produce large amounts of lactic acid, which is related to its ability to maintain a higher pH (Valli et al., 2006). Contrary to this finding, various yeasts are known to produce low amounts of acetic acid (Trifiro et al., 1997). 

Thomas, K.C., Hynes, S.H., and Ingledew, W.M. 2002. Influence of medium buffering capacity on inhibition of Saccharomyces cerevisiae growth by acetic and lactic acids. Applied and Environmental Microbiology 68 1616-1623. 

One of the most important processes in the production of biochemicals is the 40,000 tons/yr lactic acid production involving the Lactobacillus oxidation of lactose. The MBR productivity increased eightfold compared to a conventional batch reactor with a 19-fold increased biomass concentration. Even a 30-fold increased production of ethanol was found upon coupling the Saccharomyces cerevisiae fermentation to a membrane separation. Other successful industrial applications involve the pathogen-free production of growth hormones, the synthesis of homochiral cyanohydrins, the production of 1-aspartic acid, phenyl-acetylcarbinol, vitamin B12, and the bio transformation of acrylonitrile to acrylamide. 

Skory, C. D. (2003). Lactic acid production by Saccharomyces cerevisiae expressing a Rhizopus orizae lactate dehydrogenase gene. Journal of Industrial Microbiology Biotechnology., 30, 22 27. 

Generation of Engineered Strains of Saccharomyces cerevisiae for Lactic acid, Xylitol, and Strictosidine Production... 

During ethanol fermentations, yeasts suffer from various stresses. Ethanol as the major metabolic product of yeast fermentation accumulates in the cell and acts as a potent chemical stress towards the yeast cell. Further, temperatures higher than 35 °C, pH values below 3.5, acetic acid produced either by the yeast itself or by contaminants such as lactic acid bacteria or wild yeasts, lactic acid and osmotic pressure have a negative impact on the ethanol production by Saccharomyces cerevisiae. 

Table VI shows the results of the three continuous fermentations completed with the r424A organism. The carbon source in the fermentation media was corn fiber hydrolysate produced by the initial hydrolysis method followed by secondary acid hydrolysis. The yeast metabolized over 60% of the total carbohydrates with a g ethanol/g carbohydrate yield between 0.50 and 0.55. The lower percentage of total carbohydrates metabolized is likely due to the continuous fermentation method, as shake flask fermentations, albeit at lower dry solids, metabolized up to 91% of the carbohydrates (unpublished data). The carbohydrate utilization will be optimized in future fermentations. The g/g yield is near theoretical, therefore the metabolized carbohydrate is converted solely to ethanol. The organic acids, ethanol and dextrose concentrations for a sample fermentation are shown in Figure 1. The ethanol concentration in the fermentor at the end of the run was 55g/L. The concentrations of the citric acid, lactic acid and glycerol increase substantially during the fermentation, which are normal byproducts of the ethanol fermentation by Saccharomyces cerevisiae. The volume of the fermentation was doubled with hydrolysate fed into the fermentor. These fermentations show that the organism can ferment the glucose and xylose from the corn fiber hydrolysate to ethanol without detoxification of the hydrolysate. The fermentation conditions were not optimized, so additional improvement in the fermentation is expected.

Bueno, D. J., Casale, C. H., Pizzolitto, R. R, Salvano, M. A., Oliver, G. (2007). Physical adsorption of aflatoxin Bj by lactic acid bacteria and Saccharomyces cerevisiae a theoretical model. Journal of Food Protection, 70(9), 2148-2154. 

Shetty, P. H., Jespersen, L. (2006). Saccharomyces cerevisiae and lactic acid bacteria as potential mycotoxin decontaminating agents. Trends in Food Science Technology, 17, 48-55. 

This chapter is divided into five sections including an introdnction (Section 17.1), impact of yeast on beer appearance (Section 17.2), impact of yeast on beer flavour (Section 17.3), impact of bacteria on beer appearance and flavour (Section 17.4), and future trends (Section 17.5). The emphasis is on the impact of yeast on beer appearance and flavour because more information is available on this topic. Although most of the discussions are centred on the impact of main brewing yeast strains (Saccharomyces cerevisiae and Saccharomycespastorianus) on barley malt-based beers (ale and lager, respectively) (Lodolo, Kock, Axcell, Brooks, 2008 Stewart, Hill, Russell, 2013), references are also made to other yeasts involved in brewing specialty beers derived from both barley malt and other cereal malts. Lactic acid bacteria (LAB) are the focus of discussion with regard to bacterial impact on beer appearance and flavour due to their relatively common occurrences in beers (Menz et al., 2010 Sakamoto Konings, 2003 Suzuki, 2011 Suzuki, Asano, lijima, Kitamoto, 2008). 

Adachi E, Torigoe M, Sugiyama M, Nikawa J, Shimizu K. (1998). Modification of metabolic pathways of Saccharomyces cerevisiae by the expression of lactate dehydrogenase and deletion of pyruvate decarboxylase genes for the lactic acid fermentation at low pH value. J Ferment Bioeng, 86, 284-289. 

Dequin S, Bane P. (1994). Mixed lactic acid-alcoholic fermentation by Saccharomyces cerevisiae expressing the Lactobacillus casei L(-l-)-LDH. Biotechnology, 12, 173-177. 

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