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Prenylated (iso)flavonoids as antifungal agents against the food spoiler Zygosaccharomyces parabailii. Food Control 2022. [DOI: 10.1016/j.foodcont.2021.108434] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
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2
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Seekles SJ, van Dam J, Arentshorst M, Ram AFJ. Natural Variation and the Role of Zn 2Cys 6 Transcription Factors SdrA, WarA and WarB in Sorbic Acid Resistance of Aspergillus niger. Microorganisms 2022; 10:microorganisms10020221. [PMID: 35208676 PMCID: PMC8877037 DOI: 10.3390/microorganisms10020221] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2021] [Revised: 01/16/2022] [Accepted: 01/18/2022] [Indexed: 02/07/2023] Open
Abstract
Weak acids, such as sorbic acid, are used as chemical food preservatives by the industry. Fungi overcome this weak-acid stress by inducing cellular responses mediated by transcription factors. In our research, a large-scale sorbic acid resistance screening was performed on 100 A. niger sensu stricto strains isolated from various sources to study strain variability in sorbic acid resistance. The minimal inhibitory concentration of undissociated (MICu) sorbic acid at pH = 4 in the MEB of the A. niger strains varies between 4.0 mM and 7.0 mM, with the average out of 100 strains being 4.8 ± 0.8 mM, when scored after 28 days. MICu values were roughly 1 mM lower when tested in commercial ice tea. Genome sequencing of the most sorbic-acid-sensitive strain among the isolates revealed a premature stop codon inside the sorbic acid response regulator encoding gene sdrA. Repairing this missense mutation increased the sorbic acid resistance, showing that the sorbic-acid-sensitive phenotype of this strain is caused by the loss of SdrA function. To identify additional transcription factors involved in weak-acid resistance, a transcription factor knock-out library consisting of 240 A. niger deletion strains was screened. The screen identified a novel transcription factor, WarB, which contributes to the resistance against a broad range of weak acids, including sorbic acid. The roles of SdrA, WarA and WarB in weak-acid resistance, including sorbic acid, were compared by creating single, double and the triple knock-out strains. All three transcription factors were found to have an additive effect on the sorbic acid stress response.
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Affiliation(s)
- Sjoerd J. Seekles
- TIFN, Agro Business Park 82, 6708 PW Wageningen, The Netherlands;
- Department Molecular Microbiology and Biotechnology, Institute of Biology, Leiden University, Sylviusweg 72, 2333 BE Leiden, The Netherlands; (J.v.D.); (M.A.)
| | - Jisca van Dam
- Department Molecular Microbiology and Biotechnology, Institute of Biology, Leiden University, Sylviusweg 72, 2333 BE Leiden, The Netherlands; (J.v.D.); (M.A.)
| | - Mark Arentshorst
- Department Molecular Microbiology and Biotechnology, Institute of Biology, Leiden University, Sylviusweg 72, 2333 BE Leiden, The Netherlands; (J.v.D.); (M.A.)
| | - Arthur F. J. Ram
- TIFN, Agro Business Park 82, 6708 PW Wageningen, The Netherlands;
- Department Molecular Microbiology and Biotechnology, Institute of Biology, Leiden University, Sylviusweg 72, 2333 BE Leiden, The Netherlands; (J.v.D.); (M.A.)
- Correspondence:
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Benjamim da Silva É, Costa DM, Santos EM, Moyer K, Hellings E, Kung L. The effects of Lactobacillus hilgardii 4785 and Lactobacillus buchneri 40788 on the microbiome, fermentation, and aerobic stability of corn silage ensiled for various times. J Dairy Sci 2021; 104:10678-10698. [PMID: 34334198 DOI: 10.3168/jds.2020-20111] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2020] [Accepted: 06/14/2021] [Indexed: 01/04/2023]
Abstract
We evaluated the ability of an inoculant containing a combination of Lactobacillus hilgardii and Lactobacillus buchneri to modify the microbiome and improve the aerobic stability of whole-plant corn silage after various lengths of ensiling. Chopped whole-plant corn at about 33% dry matter (DM) was uninoculated (CTR) or inoculated with L. hilgardii CNCM I-4785 and L. buchneri NCIMB 40788 at 200,000 cfu/g of fresh forage weight each (combined application rate of 400,000 cfu of lactic acid bacteria/g of fresh forage weight; LHLB), L. buchneri NCIMB 40788 at 400,000 cfu/g of fresh forage weight and Pediococcus pentosaceus NCIMB 12455 at 100,000 cfu/g of fresh forage weight, used as a positive control (LB500), L. hilgardii CNCM I-4785 at the application rate used in the LHLB formulation of 200,000 cfu/g of fresh forage weight (LH), or L. buchneri NCIMB 40788 at the application rate used in the LHLB formulation of 200,000 cfu/g of fresh forage weight (LB). Silos were opened after 34 and 99 d of ensiling and analyzed for nutrient composition, fermentation profile, microbiome, and aerobic stability. After 34 d of ensiling, the inoculated silages had greater numbers of culturable lactic acid bacteria, a bacterial community less rich and diverse, greater relative abundance of Lactobacillus, lower relative abundance of Klebsiella, and a greater concentration of propionic acid than uninoculated silages. Inoculation decreased the ratio of lactic acid to acetic acid, except for LB alone. Treatment LHLB resulted in silage with a greater concentration of 1,2-propanediol than LB500 and was the only treatment to have a lower relative abundance of Saccharomycetes compared with uninoculated silage. Treatments LHLB and LB500 improved the aerobic stability compared with CTR, but the individual LH and LB treatments applied at a low dose did not. Whereas LB500 was stable 34 h longer than CTR, LHLB was stable 91 h longer. After 99 d of ensiling, all inoculated silages had markedly greater aerobic stability than uninoculated silage and were stable for more than 360 h. The inoculant containing a combination of L. hilgardii and L. buchneri markedly improved the aerobic stability of corn silage after a relatively short period of ensiling, and such improvements were greater than the ones obtained from inoculation with the combination of L. buchneri and P. pentosaceus. Inoculating with the combination of L. hilgardii and L. buchneri may be helpful to producers that must feed silage shortly after ensiling.
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Affiliation(s)
| | - Daviane Martinele Costa
- Department of Animal and Food Sciences, University of Delaware, Newark 19716; Department of Animal Sciences, Federal University of Lavras, Lavras, MG, Brazil 37200-900
| | - Edson Mauro Santos
- Department of Animal and Food Sciences, University of Delaware, Newark 19716; Department of Animal Sciences, Federal University of Paraíba, Areia, PB, Brazil 58397-000
| | - Kassandra Moyer
- Department of Animal and Food Sciences, University of Delaware, Newark 19716
| | - Elizabeth Hellings
- Department of Animal and Food Sciences, University of Delaware, Newark 19716
| | - Limin Kung
- Department of Animal and Food Sciences, University of Delaware, Newark 19716.
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Labuschagne P, Divol B. Thiamine: a key nutrient for yeasts during wine alcoholic fermentation. Appl Microbiol Biotechnol 2021; 105:953-973. [PMID: 33404836 DOI: 10.1007/s00253-020-11080-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2020] [Revised: 12/18/2020] [Accepted: 12/27/2020] [Indexed: 12/27/2022]
Abstract
Alcoholic fermentation is a crucial step of winemaking, during which yeasts convert sugars to alcohol and also produce or biotransform numerous flavour compounds. In this context, nutrients are essential compounds to support yeast growth and ultimately ensure complete fermentation, as well as optimized production of flavour compounds over that of off-flavour compounds. In particular, the vitamin thiamine not only plays an essential cofactor role for several enzymes involved in various metabolic pathways, including those leading to the production of wine-relevant flavour compounds, but also aids yeast survival via thiamine-dependent stress protection functions. Most yeast species are able to both assimilate exogenous thiamine into the cell and synthesize thiamine de novo. However, the mechanism and level of thiamine accumulation depend on several factors. This review provides an in-depth overview of thiamine utilization and metabolism in the model yeast species Saccharomyces cerevisiae, as well as the current knowledge on (1) the intracellular functions of thiamine, (2) the balance between and regulation of uptake and synthesis of thiamine and (3) the multitude of factors influencing thiamine availability and utilization. For the latter, a particular emphasis is placed on conditions occurring during wine fermentation. The adequacy of thiamine concentration in grape must to ensure successful fermentation is discussed together with the effect of thiamine concentration on fermentation kinetics and on wine sensory properties. This knowledge may serve as a resource to optimise thiamine concentrations for optimal industrial application of yeasts. KEY POINTS: • Thiamine uptake is preferred over biosynthesis and is transcriptionally repressed. • Multiple factors affect thiamine synthesis, availability and uptake for wine yeast. • Thiamine availability impacts fermentation kinetics and wine's sensory properties.
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Affiliation(s)
- Pwj Labuschagne
- South African Grape and Wine Research Institute, Department of Viticulture and Oenology, Private Bag X1, Matieland, 7602, South Africa
| | - B Divol
- South African Grape and Wine Research Institute, Department of Viticulture and Oenology, Private Bag X1, Matieland, 7602, South Africa.
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Abstract
Traditional sour beers are produced by spontaneous fermentations involving numerous yeast and bacterial species. One of the traits that separates sour beers from ales and lagers is the high concentration of organic acids such as lactic acid and acetic acid, which results in reduced pH and increased acidic taste. Several challenges complicate the production of sour beers through traditional methods. These include poor process control, lack of consistency in product quality, and lengthy fermentation times. This review summarizes the methods for traditional sour beer production with a focus on the use of lactobacilli to generate this beverage. In addition, the review describes the use of selected pure cultures of microorganisms with desirable properties in conjunction with careful application of processing steps. Together, this facilitates the production of sour beer with a higher level of process control and more rapid fermentation compared to traditional methods.
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Lewis HL, Johnson GT. Growth and Oxygen-Uptake Responses of Cunninghamella Echinulata on Even-Chain Fatty Acids. Mycologia 2018. [DOI: 10.1080/00275514.1967.12018473] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Affiliation(s)
- Harold L. Lewis
- Department of Botany and Bacteriology University of Arkansas Fayetteville, Arkansas
| | - G. T. Johnson
- Department of Botany and Bacteriology University of Arkansas Fayetteville, Arkansas
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Lewis HL, Johnson GT. Reversal of Inhibition of Endogenous Respiration of Cunninghamella Echinulata by Intermediate-Chain-Length Fatty Acids. Mycologia 2018. [DOI: 10.1080/00275514.1968.12018579] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Affiliation(s)
- Harold L. Lewis
- Department of Biology, Texas Technological College, Lubbock, Texas
| | - G. T. Johnson
- Department of Botany and Bacteriology, University of Arkansas, Fayetteville, Arkansas
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Affiliation(s)
- Antonio Leal
- Plant Pathology, West Virginia University, Morgantown, West Virginia 26506
| | - V. G. Lilly
- Plant Pathology, West Virginia University, Morgantown, West Virginia 26506
| | - M. E. Gallegly
- Plant Pathology, West Virginia University, Morgantown, West Virginia 26506
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Yu JL, Qian ZG, Zhong JJ. Advances in bio-based production of dicarboxylic acids longer than C4. Eng Life Sci 2018; 18:668-681. [PMID: 32624947 DOI: 10.1002/elsc.201800023] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2018] [Revised: 05/18/2018] [Accepted: 06/13/2018] [Indexed: 12/15/2022] Open
Abstract
Growing concerns of environmental pollution and fossil resource shortage are major driving forces for bio-based production of chemicals traditionally from petrochemical industry. Dicarboxylic acids (DCAs) are important platform chemicals with large market and wide applications, and here the recent advances in bio-based production of straight-chain DCAs longer than C4 from biological approaches, especially by synthetic biology, are reviewed. A couple of pathways were recently designed and demonstrated for producing DCAs, even those ranging from C5 to C15, by employing respective starting units, extending units, and appropriate enzymes. Furthermore, in order to achieve higher production of DCAs, enormous efforts were made in engineering microbial hosts that harbored the biosynthetic pathways and in improving properties of biocatalytic elements to enhance metabolic fluxes toward target DCAs. Here we summarize and discuss the current advantages and limitations of related pathways, and also provide perspectives on synthetic pathway design and optimization for hyper-production of DCAs.
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Affiliation(s)
- Jia-Le Yu
- State Key Laboratory of Microbial Metabolism Joint International Research Laboratory of Metabolic and Developmental Sciences, School of Life Sciences and Biotechnology Shanghai Jiao Tong University Shanghai P. R. China.,State Key Laboratory of Bioreactor Engineering, School of Biotechnology East China University of Science and Technology Shanghai P. R. China
| | - Zhi-Gang Qian
- State Key Laboratory of Microbial Metabolism Joint International Research Laboratory of Metabolic and Developmental Sciences, School of Life Sciences and Biotechnology Shanghai Jiao Tong University Shanghai P. R. China.,Shanghai Collaborative Innovation Center for Biomanufacturing Technology (SCICBT) East China University of Science and Technology Shanghai P. R. China
| | - Jian-Jiang Zhong
- State Key Laboratory of Microbial Metabolism Joint International Research Laboratory of Metabolic and Developmental Sciences, School of Life Sciences and Biotechnology Shanghai Jiao Tong University Shanghai P. R. China.,State Key Laboratory of Bioreactor Engineering, School of Biotechnology East China University of Science and Technology Shanghai P. R. China.,Shanghai Collaborative Innovation Center for Biomanufacturing Technology (SCICBT) East China University of Science and Technology Shanghai P. R. China
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Kung L, Smith ML, Benjamim da Silva E, Windle MC, da Silva TC, Polukis SA. An evaluation of the effectiveness of a chemical additive based on sodium benzoate, potassium sorbate, and sodium nitrite on the fermentation and aerobic stability of corn silage. J Dairy Sci 2018; 101:5949-5960. [DOI: 10.3168/jds.2017-14006] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2017] [Accepted: 02/26/2018] [Indexed: 11/19/2022]
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Improved microscale cultivation of Pichia pastoris for clonal screening. Fungal Biol Biotechnol 2018; 5:8. [PMID: 29750118 PMCID: PMC5932850 DOI: 10.1186/s40694-018-0053-6] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2017] [Accepted: 03/28/2018] [Indexed: 11/10/2022] Open
Abstract
Background Expanding the application of technical enzymes, e.g., in industry and agriculture, commands the acceleration and cost-reduction of bioprocess development. Microplates and shake flasks are massively employed during screenings and early phases of bioprocess development, although major drawbacks such as low oxygen transfer rates are well documented. In recent years, miniaturization and parallelization of stirred and shaken bioreactor concepts have led to the development of novel microbioreactor concepts. They combine high cultivation throughput with reproducibility and scalability, and represent promising tools for bioprocess development. Results Parallelized microplate cultivation of the eukaryotic protein production host Pichia pastoris was applied effectively to support miniaturized phenotyping of clonal libraries in batch as well as fed-batch mode. By tailoring a chemically defined growth medium, we show that growth conditions are scalable from microliter to 0.8 L lab-scale bioreactor batch cultivation with different carbon sources. Thus, the set-up allows for a rapid physiological comparison and preselection of promising clones based on online data and simple offline analytics. This is exemplified by screening a clonal library of P. pastoris constitutively expressing AppA phytase from Escherichia coli. The protocol was further modified to establish carbon-limited conditions by employing enzymatic substrate-release to achieve screening conditions relevant for later protein production processes in fed-batch mode. Conclusion The comparison of clonal rankings under batch and fed-batch-like conditions emphasizes the necessity to perform screenings under process-relevant conditions. Increased biomass and product concentrations achieved after fed-batch microscale cultivation facilitates the selection of top producers. By reducing the demand to conduct laborious and cost-intensive lab-scale bioreactor cultivations during process development, this study will contribute to an accelerated development of protein production processes. Electronic supplementary material The online version of this article (10.1186/s40694-018-0053-6) contains supplementary material, which is available to authorized users.
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Narendranath NV, Thomas KC, Ingledew WM. Acetic Acid and Lactic Acid Inhibition of Growth ofSaccharomyces Cerevisiaeby Different Mechanisms. JOURNAL OF THE AMERICAN SOCIETY OF BREWING CHEMISTS 2018. [DOI: 10.1094/asbcj-59-0187] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Affiliation(s)
- Neelakantam V. Narendranath
- Department of Applied Microbiology and Food Science, University of Saskatchewan, Saskatoon, SK, Canada S7N 5A8
| | - Kolothumannil C. Thomas
- Department of Applied Microbiology and Food Science, University of Saskatchewan, Saskatoon, SK, Canada S7N 5A8
| | - W. Michael Ingledew
- Department of Applied Microbiology and Food Science, University of Saskatchewan, Saskatoon, SK, Canada S7N 5A8
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Mieszkin S, Hymery N, Debaets S, Coton E, Le Blay G, Valence F, Mounier J. Action mechanisms involved in the bioprotective effect of Lactobacillus harbinensis K.V9.3.1.Np against Yarrowia lipolytica in fermented milk. Int J Food Microbiol 2017; 248:47-55. [DOI: 10.1016/j.ijfoodmicro.2017.02.013] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2016] [Revised: 12/16/2016] [Accepted: 02/20/2017] [Indexed: 10/20/2022]
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Modeling of exo-inulinase biosynthesis by Kluyveromyces marxianus in fed-batch mode: correlating production kinetics and metabolic heat fluxes. Appl Microbiol Biotechnol 2016; 101:1877-1887. [PMID: 27844140 DOI: 10.1007/s00253-016-7971-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2016] [Revised: 10/12/2016] [Accepted: 10/24/2016] [Indexed: 10/20/2022]
Abstract
A metabolic heat-based model was used for estimating the growth of Kluyveromyces marxianus, and the modified Luedeking-Piret kinetic model was used for describing the inulinase production kinetics. For the first time, a relationship was developed to relate inulinase production kinetics directly to metabolic heat generated, which corroborated well with the experimental data (with R 2 values of above 0.9). It also demonstrated the predominantly growth-associated nature of the inulinase production with Luedeking-Piret parameters α and β, having values of 0.75 and 0.033, respectively, in the exponential feeding experiment. MATLAB was used for simulating the inulinase production kinetics which demonstrated the model's utility in performing real-time prediction of inulinase concentration with metabolic heat data as input. To validate the model predictions, a biocalorimetric (Bio RC1e) experiment for inulinase production by K. marxianus was performed. The inulinase concentration (IU/mL) values acquired from the model in were validated with the experimental values and the metabolic heat data. This modeling approach enabled the optimization, monitoring, and control of inulinase production process using the real-time biocalorimetric (Bio RC1e) data. Gas chromatography and mass spectrometry analysis were carried out to study the overflow metabolism taking place in K. marxianus inulinase production.
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Boss PK, Pearce AD, Zhao Y, Nicholson EL, Dennis EG, Jeffery DW. Potential grape-derived contributions to volatile ester concentrations in wine. Molecules 2015; 20:7845-73. [PMID: 25939071 PMCID: PMC6272246 DOI: 10.3390/molecules20057845] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2015] [Revised: 04/23/2015] [Accepted: 04/23/2015] [Indexed: 11/25/2022] Open
Abstract
Grape composition affects wine flavour and aroma not only through varietal compounds, but also by influencing the production of volatile compounds by yeast. C9 and C12 compounds that potentially influence ethyl ester synthesis during fermentation were studied using a model grape juice medium. It was shown that the addition of free fatty acids, their methyl esters or acyl-carnitine and acyl-amino acid conjugates can increase ethyl ester production in fermentations. The stimulation of ethyl ester production above that of the control was apparent when lower concentrations of the C9 compounds were added to the model musts compared to the C12 compounds. Four amino acids, which are involved in CoA biosynthesis, were also added to model grape juice medium in the absence of pantothenate to test their ability to influence ethyl and acetate ester production. β-Alanine was the only one shown to increase the production of ethyl esters, free fatty acids and acetate esters. The addition of 1 mg∙L−1 β-alanine was enough to stimulate production of these compounds and addition of up to 100 mg∙L−1 β-alanine had no greater effect. The endogenous concentrations of β-alanine in fifty Cabernet Sauvignon grape samples exceeded the 1 mg∙L−1 required for the stimulatory effect on ethyl and acetate ester production observed in this study.
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Affiliation(s)
- Paul K Boss
- CSIRO Agriculture Flagship, PMB 2, Glen Osmond, SA 5064, Australia.
| | - Anthony D Pearce
- School of Agriculture, Food and Wine, Waite Research Institute, The University of Adelaide, PMB 1, Glen Osmond, SA 5064, Australia.
- South Australian Research and Development Institute, GPO Box 397, Adelaide, SA 5001, Australia.
| | - Yanjia Zhao
- School of Agriculture, Food and Wine, Waite Research Institute, The University of Adelaide, PMB 1, Glen Osmond, SA 5064, Australia.
| | | | - Eric G Dennis
- CSIRO Agriculture Flagship, PMB 2, Glen Osmond, SA 5064, Australia.
- Department of Chemistry, The University of British Columbia, Okanagan Campus, 3333 University Way, Kelowna, BC V1V 1V7, Canada.
| | - David W Jeffery
- School of Agriculture, Food and Wine, Waite Research Institute, The University of Adelaide, PMB 1, Glen Osmond, SA 5064, Australia.
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Franden MA, Pilath HM, Mohagheghi A, Pienkos PT, Zhang M. Inhibition of growth of Zymomonas mobilis by model compounds found in lignocellulosic hydrolysates. BIOTECHNOLOGY FOR BIOFUELS 2013; 6:99. [PMID: 23837621 PMCID: PMC3716709 DOI: 10.1186/1754-6834-6-99] [Citation(s) in RCA: 96] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/15/2013] [Accepted: 06/24/2013] [Indexed: 05/18/2023]
Abstract
BACKGROUND During the pretreatment of biomass feedstocks and subsequent conditioning prior to saccharification, many toxic compounds are produced or introduced which inhibit microbial growth and in many cases, production of ethanol. An understanding of the toxic effects of compounds found in hydrolysate is critical to improving sugar utilization and ethanol yields in the fermentation process. In this study, we established a useful tool for surveying hydrolysate toxicity by measuring growth rates in the presence of toxic compounds, and examined the effects of selected model inhibitors of aldehydes, organic and inorganic acids (along with various cations), and alcohols on growth of Zymomonas mobilis 8b (a ZM4 derivative) using glucose or xylose as the carbon source. RESULTS Toxicity strongly correlated to hydrophobicity in Z. mobilis, which has been observed in Escherichia coli and Saccharomyces cerevisiae for aldehydes and with some exceptions, organic acids. We observed Z. mobilis 8b to be more tolerant to organic acids than previously reported, although the carbon source and growth conditions play a role in tolerance. Growth in xylose was profoundly inhibited by monocarboxylic organic acids compared to growth in glucose, whereas dicarboxylic acids demonstrated little or no effects on growth rate in either substrate. Furthermore, cations can be ranked in order of their toxicity, Ca++ > > Na+ > NH4+ > K+. HMF (5-hydroxymethylfurfural), furfural and acetate, which were observed to contribute to inhibition of Z. mobilis growth in dilute acid pretreated corn stover hydrolysate, do not interact in a synergistic manner in combination. We provide further evidence that Z. mobilis 8b is capable of converting the aldehydes furfural, vanillin, 4-hydroxybenzaldehyde and to some extent syringaldehyde to their alcohol forms (furfuryl, vanillyl, 4-hydroxybenzyl and syringyl alcohol) during fermentation. CONCLUSIONS Several key findings in this report provide a mechanism for predicting toxic contributions of inhibitory components of hydrolysate and provide guidance for potential process development, along with potential future strain improvement and tolerance strategies.
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Affiliation(s)
- Mary Ann Franden
- National Bioenergy Center, National Renewable Energy Laboratory, 15013 Denver West Parkway, Golden, CO 80401, USA
| | - Heidi M Pilath
- National Bioenergy Center, National Renewable Energy Laboratory, 15013 Denver West Parkway, Golden, CO 80401, USA
| | - Ali Mohagheghi
- National Bioenergy Center, National Renewable Energy Laboratory, 15013 Denver West Parkway, Golden, CO 80401, USA
| | - Philip T Pienkos
- National Bioenergy Center, National Renewable Energy Laboratory, 15013 Denver West Parkway, Golden, CO 80401, USA
| | - Min Zhang
- National Bioenergy Center, National Renewable Energy Laboratory, 15013 Denver West Parkway, Golden, CO 80401, USA
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Vriesekoop F, Krahl M, Hucker B, Menz G. 125thAnniversary Review: Bacteria in brewing: The good, the bad and the ugly. JOURNAL OF THE INSTITUTE OF BREWING 2013. [DOI: 10.1002/jib.49] [Citation(s) in RCA: 71] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Affiliation(s)
- Frank Vriesekoop
- Department of Food Science and Agri-Food Supply Chain Management; Harper Adams University; Newport TF10 8NB UK
- School of Health Sciences; University of Ballarat; Ballarat Victoria Australia
| | | | - Barry Hucker
- School of Health Sciences; University of Ballarat; Ballarat Victoria Australia
| | - Garry Menz
- School of Health Sciences; University of Ballarat; Ballarat Victoria Australia
- Carlton and United Breweries; Yatala Brewery; Yatala Queensland Australia
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Stratford M, Nebe-von-Caron G, Steels H, Novodvorska M, Ueckert J, Archer DB. Weak-acid preservatives: pH and proton movements in the yeast Saccharomyces cerevisiae. Int J Food Microbiol 2012; 161:164-71. [PMID: 23334094 DOI: 10.1016/j.ijfoodmicro.2012.12.013] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2012] [Revised: 11/19/2012] [Accepted: 12/06/2012] [Indexed: 10/27/2022]
Abstract
Weak-acid preservatives commonly used to prevent fungal spoilage of low pH foods include sorbic and acetic acids. The "classical weak-acid theory" proposes that weak acids inhibit spoilage organisms by diffusion of undissociated acids through the membrane, dissociation within the cell to protons and anions, and consequent acidification of the cytoplasm. Results from 25 strains of Saccharomyces cerevisiae confirmed inhibition by acetic acid at a molar concentration 42 times higher than sorbic acid, in contradiction of the weak-acid theory where all acids of equal pK(a) should inhibit at equimolar concentrations. Flow cytometry showed that the intracellular pH fell to pH 4.7 at the growth-inhibitory concentration of acetic acid, whereas at the inhibitory concentration of sorbic acid, the pH only fell to pH 6.3. The plasma membrane H⁺-ATPase proton pump (Pma1p) was strongly inhibited by sorbic acid at the growth-inhibitory concentration, but was stimulated by acetic acid. The H⁺-ATPase was also inhibited by lower sorbic acid concentrations, but later showed recovery and elevated activity if the sorbic acid was removed. Levels of PMA1 transcripts increased briefly following sorbic acid addition, but soon returned to normal levels. It was concluded that acetic acid inhibition of S. cerevisiae was due to intracellular acidification, in accord with the "classical weak-acid theory". Sorbic acid, however, appeared to be a membrane-active antimicrobial compound, with the plasma membrane H⁺-ATPase proton pump being a primary target of inhibition. Understanding the mechanism of action of sorbic acid will hopefully lead to improved methods of food preservation.
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Affiliation(s)
- Malcolm Stratford
- School of Biology, University of Nottingham, University Park, Nottingham NG7 2RD, United Kingdom.
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Ullah A, Orij R, Brul S, Smits GJ. Quantitative analysis of the modes of growth inhibition by weak organic acids in Saccharomyces cerevisiae. Appl Environ Microbiol 2012; 78:8377-87. [PMID: 23001666 PMCID: PMC3497387 DOI: 10.1128/aem.02126-12] [Citation(s) in RCA: 105] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2012] [Accepted: 09/17/2012] [Indexed: 11/20/2022] Open
Abstract
Weak organic acids are naturally occurring compounds that are commercially used as preservatives in the food and beverage industries. They extend the shelf life of food products by inhibiting microbial growth. There are a number of theories that explain the antifungal properties of these weak acids, but the exact mechanism is still unknown. We set out to quantitatively determine the contributions of various mechanisms of antifungal activity of these weak acids, as well as the mechanisms that yeast uses to counteract their effects. We analyzed the effects of four weak organic acids differing in lipophilicity (sorbic, benzoic, propionic, and acetic acids) on growth and intracellular pH (pH(i)) in Saccharomyces cerevisiae. Although lipophilicity of the acids correlated with the rate of acidification of the cytosol, our data confirmed that not initial acidification, but rather the cell's ability to restore pH(i), was a determinant for growth inhibition. This pH(i) recovery in turn depended on the nature of the organic anion. We identified long-term acidification as the major cause of growth inhibition under acetic acid stress. Restoration of pH(i), and consequently growth rate, in the presence of this weak acid required the full activity of the plasma membrane ATPase Pma1p. Surprisingly, the proposed anion export pump Pdr12p was shown to play an important role in the ability of yeast cells to restore the pH(i) upon lipophilic (sorbic and benzoic) acid stress, probably through a charge interaction of anion and proton transport.
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Affiliation(s)
- Azmat Ullah
- Department of Molecular Biology and Microbial Food Safety, Swammerdam Institute for Life Sciences, Netherlands Institute for Systems Biology, University of Amsterdam, Amsterdam, the Netherlands
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Scott WA, Metzenberg RL. Location of Aryl Sulfatase in Conidia and Young Mycelia of Neurospora crassa. J Bacteriol 2010; 104:1254-65. [PMID: 16559101 PMCID: PMC248285 DOI: 10.1128/jb.104.3.1254-1265.1970] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Aryl sulfatase (arylsulfate sulfohydrolase, EC 3.1.6.1) was found to have multiple locations in Neurospora conidia. Some enzyme activity remained in the supernatant when a spore suspension was centrifuged or filtered. Part of the cell-bound activity could be detected by adding the assay ingredients to a suspension of intact spores (patent enzyme), and additional activity was only detectable when the spores were first treated to destroy their permeability barriers (cryptic enzyme). Such treatments include: disruption with an X-press, brief rinsing with chloroform or acetone, incubation at 60 C for 5 min, and incubation with phenethyl alcohol, nystatin, or ascosin. Part of the patent aryl sulfatase was inactivated by briefly acid treating the intact spores (no loss of conidial viability). This enzyme was considered to have a cell surface location. Some enzyme was acid-resistant in intact spores, but all of the enzyme was acid-sensitive in spores whose permeability barriers had been disrupted. The pH dependence, kinetic properties, and p-nitrophenyl sulfate uptake were investigated in acid-treated conidia. No aryl sulfatase was detected in ascospores. Young mycelia contained more aryl sulfatase than did conidia, but little, if any, was secreted into the growth medium. Cryptic activity was demonstrated in young mycelia by brief chloroform treatment or by rinsing the cells with 0.1 m acetate buffer. Enzyme activity in young mycelia was completely labile to acid treatment, as was cell viability.
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Affiliation(s)
- W A Scott
- Department of Physiological Chemistry, University of Wisconsin Medical School, Madison, Wisconsin 53706
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21
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Stratford M, Plumridge A, Nebe-von-Caron G, Archer DB. Inhibition of spoilage mould conidia by acetic acid and sorbic acid involves different modes of action, requiring modification of the classical weak-acid theory. Int J Food Microbiol 2009; 136:37-43. [PMID: 19846233 DOI: 10.1016/j.ijfoodmicro.2009.09.025] [Citation(s) in RCA: 67] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2009] [Revised: 09/21/2009] [Accepted: 09/27/2009] [Indexed: 10/20/2022]
Abstract
Fungal spoilage of many foods is prevented by weak-acid preservatives such as sorbic acid or acetic acid. We show that sorbic and acetic acids do not both inhibit cells by lowering of internal pH alone and that the "classical weak-acid theory" must be revised. The "classical weak-acid theory" suggests that all lipophilic acids with identical pK(a) values are equally effective as preservatives, causing inhibition by diffusion of molecular acids into the cell, dissociation, and subsequent acidification of the cytoplasm. Using a number of spoilage fungi from different genera, we have shown that sorbic acid was far more toxic than acetic acid, and no correlation existed between resistance to acetic acid and resistance to sorbic acid. The molar ratio of minimum inhibitory concentrations (MICs) (acetic: sorbic) was 58 for Paecilomyces variotii and 14 for Aspergillus phoenicis. Using flow cytometry on germinating conidia of Aspergillusniger, acetic acid at pH 4.0 caused an immediate decline in the mean cytoplasmic pH (pH(i)) falling from neutrality to approximately pH 4.7 at the MIC (80 mM). Sorbic acid also caused a rapid but far smaller drop in pH(i), at the MIC (4.5 mM); the pH remained above pH 6.3. Over 0-5 mM, a number of other weak acids caused a similar fall in cytoplasmic pH. It was concluded that while acetic acid inhibition of A. niger conidia was due to cytoplasmic acidification, inhibition by sorbic acid was not. A possible membrane-mediated mode of action of sorbic acid is discussed.
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Affiliation(s)
- Malcolm Stratford
- School of Biology, University of Nottingham, University Park, Nottingham, United Kingdom.
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22
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Dang T, Vermeulen A, Ragaert P, Devlieghere F. A peculiar stimulatory effect of acetic and lactic acid on growth and fermentative metabolism of Zygosaccharomyces bailii. Food Microbiol 2009; 26:320-7. [DOI: 10.1016/j.fm.2008.12.002] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2008] [Revised: 12/02/2008] [Accepted: 12/07/2008] [Indexed: 10/21/2022]
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24
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Melin P, Stratford M, Plumridge A, Archer DB. Auxotrophy for uridine increases the sensitivity of Aspergillus niger to weak-acid preservatives. Microbiology (Reading) 2008; 154:1251-1257. [DOI: 10.1099/mic.0.2007/014332-0] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Affiliation(s)
- Petter Melin
- Department of Microbiology, Swedish University of Agricultural Sciences, PO Box 7025, SE-750 07 Uppsala, Sweden
- School of Biology, University of Nottingham, University Park, Nottingham NG7 2RD, UK
| | - Malcolm Stratford
- School of Biology, University of Nottingham, University Park, Nottingham NG7 2RD, UK
| | - Andrew Plumridge
- School of Biology, University of Nottingham, University Park, Nottingham NG7 2RD, UK
| | - David B. Archer
- School of Biology, University of Nottingham, University Park, Nottingham NG7 2RD, UK
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25
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Stratford M, Plumridge A, Archer DB. Decarboxylation of sorbic acid by spoilage yeasts is associated with the PAD1 gene. Appl Environ Microbiol 2007; 73:6534-42. [PMID: 17766451 PMCID: PMC2075038 DOI: 10.1128/aem.01246-07] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The spoilage yeast Saccharomyces cerevisiae degraded the food preservative sorbic acid (2,4-hexadienoic acid) to a volatile hydrocarbon, identified by gas chromatography mass spectrometry as 1,3-pentadiene. The gene responsible was identified as PAD1, previously associated with the decarboxylation of the aromatic carboxylic acids cinnamic acid, ferulic acid, and coumaric acid to styrene, 4-vinylguaiacol, and 4-vinylphenol, respectively. The loss of PAD1 resulted in the simultaneous loss of decarboxylation activity against both sorbic and cinnamic acids. Pad1p is therefore an unusual decarboxylase capable of accepting both aromatic and aliphatic carboxylic acids as substrates. All members of the Saccharomyces genus (sensu stricto) were found to decarboxylate both sorbic and cinnamic acids. PAD1 homologues and decarboxylation activity were found also in Candida albicans, Candida dubliniensis, Debaryomyces hansenii, and Pichia anomala. The decarboxylation of sorbic acid was assessed as a possible mechanism of resistance in spoilage yeasts. The decarboxylation of either sorbic or cinnamic acid was not detected for Zygosaccharomyces, Kazachstania (Saccharomyces sensu lato), Zygotorulaspora, or Torulaspora, the genera containing the most notorious spoilage yeasts. Scatter plots showed no correlation between the extent of sorbic acid decarboxylation and resistance to sorbic acid in spoilage yeasts. Inhibitory concentrations of sorbic acid were almost identical for S. cerevisiae wild-type and Deltapad1 strains. We concluded that Pad1p-mediated sorbic acid decarboxylation did not constitute a significant mechanism of resistance to weak-acid preservatives by spoilage yeasts, even if the decarboxylation contributed to spoilage through the generation of unpleasant odors.
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Affiliation(s)
- Malcolm Stratford
- School of Biology, University of Nottingham, University Park, Nottingham NG7 2RD, United Kingdom.
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Martorell P, Stratford M, Steels H, Fernández-Espinar MT, Querol A. Physiological characterization of spoilage strains of Zygosaccharomyces bailii and Zygosaccharomyces rouxii isolated from high sugar environments. Int J Food Microbiol 2007; 114:234-42. [PMID: 17239464 DOI: 10.1016/j.ijfoodmicro.2006.09.014] [Citation(s) in RCA: 123] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2006] [Revised: 08/08/2006] [Accepted: 09/19/2006] [Indexed: 11/19/2022]
Abstract
Two isolates of spoilage yeasts Zygosaccharomyces bailii and Zygosaccharomyces rouxii were obtained from a high sugar environment, in a factory producing candied fruit and nougat. Other strains, Z. bailii from other environments and other isolates from high sugar/salt environments were obtained for comparison (Zygosaccharomyces lentus, Candida magnoliae, Candida halophila and Pichia guilliermondii). A full physiological assessment of these isolates was carried out, of preservative and biocide resistance, osmotolerance, ethanol-tolerance, low pH resistance, degree of fermentation, and growth temperature and survival to pasteurisation. Results showed that the strains isolated from high sugar environments did not show extreme physiology. These were robust strains but within the normal parameters expected for the species. One exception to this was that the Z. bailii strains were abnormally able to grow at 37 degrees C. In all strains other than C. magnolia and C. halophila, cells were able to adapt to high levels of sugar. Cultures grown in high glucose concentrations were subsequently able to tolerate higher concentrations of glucose than previously. Similarly, high sugar was found to confer a degree of protection against pasteurisation, enabling survival in what would have otherwise been a lethal treatment. Isolates of Z. bailii showed a high level of resistance to preservatives such as sorbic acid, benzoic acid, acetic acid, cinnamic acid, and ethanol, and also to heat. Unexpectedly Z. bailii isolates were not exceptionally resistant to biocides such as peracetic acid, or hypochlorite. These results indicate that spoilage by yeasts such as Z. bailii may be better prevented by use of biocidal cleaning agents in the factory, rather than treating the food with preservatives.
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Affiliation(s)
- Patricia Martorell
- Departamento de Biotecnología, Instituto de Agroquímica y Tecnología de Alimentos (CSIC), P.O. Box 73, E-46100 Burjassot, València, Spain
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27
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Hofmann KH, Babel W. Dihydroxyacetone kinase of methanol-assimilating yeasts. I. Regulation of dihydroxyacetone kinase from Candida methylica in situ. J Basic Microbiol 2007. [DOI: 10.1002/jobm.19800200605] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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28
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Steels H, James SA, Bond CJ, Roberts IN, Stratford M. Zygosaccharomyces kombuchaensis: the physiology of a new species related to the spoilage yeasts Zygosaccharomyces lentus and Zygosaccharomyces bailii. FEMS Yeast Res 2002; 2:113-21. [PMID: 12702299 DOI: 10.1111/j.1567-1364.2002.tb00076.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
Zygosaccharomyces kombuchaensis was recently discovered in the 'tea fungus' used to make fermented tea. Z. kombuchaensis was shown by ribosomal DNA sequencing to be a novel species, and a close relative of Zygosaccharomyces lentus, from which it could not be distinguished by conventional physiological tests. Z. lentus was originally established as a new taxon by growth at 4 degrees C, sensitivity for heat and oxidative stress, and lack of growth in aerobic shaken culture at temperatures above 25 degrees C. Subsequent analysis of Z. kombuchaensis reveals that this species shares these unusual characteristics, confirming its close genealogical relationship to Z. lentus. Detailed physiological data from a number of Z. kombuchaensis and Z. lentus strains clearly demonstrate that these two species can in fact be distinguished from one another based on their differing resistance/sensitivity to the food preservatives benzoic acid and sorbic acid. The spoilage yeasts Zygosaccharomyces bailii and Z. lentus are resistant to both acetic acid and sorbic acid, whereas Z. kombuchaensis is resistant to acetic acid but sensitive to sorbic acid. This would indicate that Z. kombuchaensis strains lack the mechanism for resistance to sorbic acid, but possess the means of resistance to acetic acid. This observation would therefore suggest that these two resistance mechanisms are different, and that in all probability acetic and sorbic acids inhibit yeast growth by different modes of action. Z. kombuchaensis strains were also sensitive to benzoic acid, again suggesting inhibition dissimilar from that to acetic acid.
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Affiliation(s)
- Hazel Steels
- Food Processing Group, Unilever R&D, Colworth House, Sharnbrook, Bedford MK44 1LQ, UK
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29
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Abstract
Zygosaccharomyces is a genus associated with the more extreme spoilage yeasts. Zygosaccharomyces spoilage yeasts are osmotolerant, fructophiles (preferring fructose), highly-fermentative and extremely preservative-resistant. Zygosaccharomyces bailii can grow in the presence of commonly-used food preservatives, benzoic, acetic or sorbic acids, at concentrations far higher than are legally permitted or organolepically acceptable in foods. An inoculum effect has been described for many micro-organisms and antimicrobial agents. The minimum inhibitory concentration (MIC) increases with the size of the inoculum; large inocula at high cell density therefore require considerably higher concentrations of inhibitors to prevent growth than do dilute cell suspensions. A substantial inoculum effect was found using sorbic acid against the spoilage yeast Zygosaccharomyces bailii NCYC 1766. The inoculum effect was not caused by yeasts metabolizing or adsorbing sorbic acid, thereby lowering the effective concentration; was not due to absence of cell-cell signals in dilute cell suspensions; and was not an artefact, generated by insufficient time for small inocula to grow. The inoculum effect appeared to be caused by diversity in the populations of yeast cells, with higher probability of sorbic acid-resistant cells being present in large inocula. It was found that individual cells of Zygosaccharomyces bailii populations, grown as single cells in microtitre plate wells, were very diverse, varying enormously in resistance to sorbic acid. 26S ribosomal DNA sequencing did not detect differences between the small fraction of resistant 'super cells' and the average population. Re-inoculation of the 'super cells' after overnight growth on YEPD showed a normal distribution of resistance to sorbic acid, similar to that of the original population. The resistance phenotype was therefore not heritable and not caused by a genetically distinct subpopulation. It was concluded that resistance of the spoilage yeast Zygosaccharomyces bailii to sorbic acid was due to the presence of small numbers of phenotypically resistant cells in the population.
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Affiliation(s)
- H Steels
- Microbiology Section, Unilever Research, Colworth House, Sharnbrook, Bedford MK44 1LQ, UK
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30
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Feron G, Dufosse L, Pierard E, Bonnarme P, Quere JL, Spinnler H. Production, Identification, and Toxicity of (gamma)-Decalactone and 4-Hydroxydecanoic Acid from Sporidiobolus spp. Appl Environ Microbiol 1996; 62:2826-31. [PMID: 16535376 PMCID: PMC1388914 DOI: 10.1128/aem.62.8.2826-2831.1996] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
During the bioconversion of ricinoleic acid to (gamma)-decalactone under controlled pH conditions, Sporidiobolus salmonicolor produced only the lactone form, while Sporidiobolus ruinenii produced both the lactone form and a precursor. By using gas chromatography-mass spectrometry and gas chromatography-Fourier transform infrared analysis techniques, the precursor was identified as 4-hydroxydecanoic acid. The levels of production in the presence of high concentrations of ricinoleic acid methyl ester differed in the two Sporidiobolus species. This difference was due on the one hand to the high sensitivity of S. salmonicolor to the lactone and on the other hand to the high level of 4-hydroxydecanoic acid produced by S. ruinenii. 4-Hydroxydecanoic acid is much less toxic to the microorganisms than the lactone. In contrast to S. ruinenii, S. salmonicolor is not able to catabolize 4-hydroxydecanoic acid.
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31
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Lin SJ, Lee SL, Chou CC. Effects of various fatty acid components of castor oil on the growth and production of γ-decalactone by Sporobolomyces odorus. ACTA ACUST UNITED AC 1996. [DOI: 10.1016/0922-338x(96)89452-9] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
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PODOLAK R, ZAYAS J, KASTNER C, FUNG D. REDUCTION OF LISTERIA MONOCYTOGENES, ESCHERICHIA COLI O157:H7 AND SALMONELLA TYPHIMURIUM DURING STORAGE ON BEEF SANITIZED WITH FUMARIC, ACETIC, AND LACTIC ACIDS. J Food Saf 1995. [DOI: 10.1111/j.1745-4565.1995.tb00140.x] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Xu J, Taylor KB. Effect of Nystatin on the Metabolism of Xylitol and Xylose by
Pachysolen tannophilus. Appl Environ Microbiol 1993; 59:1049-53. [PMID: 16348906 PMCID: PMC202236 DOI: 10.1128/aem.59.4.1049-1053.1993] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Ethanol production from xylitol by resting cells of
Pachysolen tannophilus
was increased 40-fold in the presence of nystatin, amphotericin B, and filipin, a group of antifungal agents that alter the permeability of the plasma membrane. Furthermore, these agents had little or no effect on ethanol formation from xylitol or xylose by the cell extract. During xylose metabolism, nystatin caused the intracellular xylitol to leak out into the medium at a 23-fold-faster rate but did not affect overall xylose utilization and CO
2
evolution. These observations explain the rate of xylitol utilization by cell extract being higher than that by whole cells (J. Xu and K. B. Taylor, Appl. Environ. Microbiol. 59:231-235, 1993) as well as the relative inability of
P. tannophilus
to utilize xylitol to support significant ethanol production and cell growth.
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Affiliation(s)
- J Xu
- Department of Biochemistry, The Fermentation Facility, The University of Alabama at Birmingham, Birmingham, Alabama 35294
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ANDERSON MAYNARDE, MARSHALL ROBERTT, DICKSON JAMESS. EFFICACIES OF ACETIC, LACTIC AND TWO MIXED ACIDS IN REDUCING NUMBER OF BACTERIA ON SURFACE OF LEARN MEAT. J Food Saf 1991. [DOI: 10.1111/j.1745-4565.1991.tb00072.x] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Kreisel H, Schauer F. [Sporothrix nivea n. sp.--a methanol- and hydrocarbon-metabolizing fungus]. J Basic Microbiol 1985; 25:653-61. [PMID: 4093875 DOI: 10.1002/jobm.3620251011] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Two fungal strains of the genus Sporothrix, isolated from industrial waste water, were characterized with respect to some morphological and physiological properties. After comparison with other species of the genus Sporothrix, the fungal strains are described as Sporothrix nivea, n. sp. Among 28 carbon sources tested, such as sugars, polysaccharides, alcohols, organic acids, and hydrocarbons, 23 are utilized. The most remarkable property of Sporothrix nivea is the utilization of both n-alkanes and methanol.
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Stafford D. The effects of mixing and volatile fatty acid concentrations on anaerobic digester performance. ACTA ACUST UNITED AC 1982. [DOI: 10.1016/0144-4565(82)90006-3] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Hofmann KH, Babel W. Dihydroxyacetone kinase of methanol-assimilating yeast. I. Regulation of dihydroxyacetone kinase from Candida methylica in situ. ZEITSCHRIFT FUR ALLGEMEINE MIKROBIOLOGIE 1980; 20:389-98. [PMID: 6252709 DOI: 10.1002/jobm.3630200605] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
In order to investigate the control behaviour of dihydroxyacetone kinase of methanol-grown Candida methylica under nearly physiological conditions kinetic and regulatory studies were carried out in situ. Yeast cells were made permeable to substrate and reaction products by treatment with Triton X-100. Normal Michaelis-Menten kinetics resulted in dependence upon the dihydroxyacetone concentration, both at the pH optimum of 7.6 and near the physiological pH-value of 6.5. The Km obtained for dihydroxyacetone was 0.02 mM, independent of the pH-value. The plots of dihydroxyacetone kinase activity as a function of the ATP concentration revealed complex kinetic characteristics with plateau regions. The maximum reaction rate was reached only after a lag time both at pH 7.6 and concentrations of ATP higher than 5 mM and at pH 6.5 and concentrations of ATP higher than 1.25 mM. Among a great number of tested metabolites no inhibitors of dihydroxyacetone kinase were found. Dihydroxyacetone kinase activity depending upon energy charge according to Atkinson exhibited curves of the U-type. These results and further data concerning the regulation of other enzymes obtained with C. methylica and other yeasts were the basis to propose a preliminary overall model of fine control of the carbon and energy metabolism of methanol-utilizing yeasts.
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Sestáková M. Growth of Candida utilis on a mixture of monosaccharides, acetic acid and ethanol as a model of waste sulphite liquor. Folia Microbiol (Praha) 1979; 24:318-27. [PMID: 43275 DOI: 10.1007/bf02926651] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Candida utilis cultivated under batch conditions in a synthetic medium with a mixture of different carbon sources utilized first D-glucose and then D-galactose, D-mannose, D-xylose, L-arabinose, ethanol and acetic acid. The effect of acetic acid was primarily a function of pH and the physiological state of the inoculum. At pH 4.5, acetic acid at a concentration of 1 g/l increased the specific growth rate, reduced time of cultivation and increased yield of the yeast dry weight. The yield from acetic acid was 61%. In the presence of a higher content of acetic acid (3--6 g/l) the yield was only 18--26%. The yield calculated only from monosaccharides increased but the yield with respect to total carbon sources was lower. The specific growth rate decreased as well. The addition of ethanol also resulted in an increase of the production and yield of the yeast dry weight but the cultivation time was prolonged. The simultaneous utilization of carbon sources of the studied mixture modelling a sulphite fermentation medium with ethanol is advantageous. However, due to physiology of the yeast, it is most suitable to cultivate a strain adapted to utilizable carbon sources in a continuous way, in the presence of their limiting concentrations in the cultivation medium.
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40
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Utilization of nitrogen sources by Aspergillus nidulans for extracellular polysaccharide production. ACTA ACUST UNITED AC 1979. [DOI: 10.1016/s0007-1536(79)80045-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Womack FC, Colowick SP. Purine nucleoside diphosphate regulation of yeast hexokinases. Arch Biochem Biophys 1978; 191:748-55. [PMID: 369462 DOI: 10.1016/0003-9861(78)90416-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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42
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Hunková Z, Fencl A. Toxic effects of fatty acids on yeast cells: possible mechanisms of action. Biotechnol Bioeng 1978; 20:1235-47. [PMID: 28799 DOI: 10.1002/bit.260200809] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
As shown in a previous paper, threshold concentrations of lower and intermediate fatty acids inhibit the uptake of inorganic phosphate, growth, and cell division in yeast cells. This demonstrates that, apart from these effects, the acids cause an increase in the respiration quotient (RQ), inhibition of CO2 fixation, production of ethanol at the expense of anabolic processes, and inhibition of active amino acid transport in the yeast Candida utilis. On the other hand, the threshold concentrations have no effect on intracellular pH. The inhibition of the inorganic phosphate uptake cannot be the sole primary mode of action of fatty acids since the omission of inorganic phosphate in the incubation medium brings about an inhibition of anabolic processes that is lower than that brought about by fatty acids since the omission of inorganic phosphate in the incubation medium brings about an inhibition of anabolic processes that is lower than that brought by fatty acids at concentrations still premitting some phosphate uptake. Although 2,4-dinitrophenol and caproic acid at low concentrations cause an analogous decrease in biomass yield, their combination does not bring about any marked increase in the effect. Considering the physicochemical properties of fatty acids and their preferential action on energy-requiring processes, one of the key sites of action can be assumed to be the mitochondrial membrane. Fatty acids might inhibit the transport of anions, especially phosphate, across the membrane, and disturb the membrane potential by affecting the transport protons. The physiocochemical properties of fatty acids may also give rise to their binding to other intracellular membranes and to a subsequent interference with the function of the corresponding organelles.
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Hunkovä Z, Fencl Z. Toxic effects of fatty acids on yeast cells: dependence of inhibitory effects on fatty acid concentration. Biotechnol Bioeng 1977; 19:1623-41. [PMID: 336112 DOI: 10.1002/bit.260191103] [Citation(s) in RCA: 27] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The yeasts Saccharomyces cerevisiae, Candida utilis, and Candida lipolytica were used to investigate the action of different concentrations of fatty acids (from acetic to myristic acid) on cell growth, division, uptake of inorganic phosphate, and substrate oxidation. The former two yeasts were found to undergo an inhibition of growth, cell division, and phosphate uptake at lower acid concentrations and to experience the inhibition of substrate oxidation at higher acid concentrations. The concentration dependence of the action of fatty acids can be classified into four categories: 1) subthreshold concentrations which do not inhibit growth and have either no effect on, or stimulate, oxygen consumption; 2) threshold concentrations which lower the rate of growth, cell division, and phosphate uptake but do not inhibit the oxidation of carbon substrate; 3) above-threshold concentrations which inhibit partially even substrate oxidation, and 4) microbicide concentrations. Candida lipolytica displays the same sensitivity toward the action of fatty acids as the above yeast species; however, the threshold concentrations are higher and can be quickly lowered owing to oxidation by the yeast. The concentrations of fatty acids found in the medium after cultivations of yeast with n-alkanes are of the same order as limiting concentrations; the formation of acids with twelve and less carbons in the molecule can thus be assumed to be one of the basic reasons for lowering of biomass yields during cultivations on these hydrocarbons.
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Lack of carbon catabolite inactivation in a mutant of Saccharomyces cerevisiae with reduced hexokinase activity. ACTA ACUST UNITED AC 1977. [DOI: 10.1007/bf00268314] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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McCutchan JA, Wunderlich A, Braude AI. Role of urinary solutes in natural immunity to gonorrhea. Infect Immun 1977; 15:149-55. [PMID: 13038 PMCID: PMC421341 DOI: 10.1128/iai.15.1.149-155.1977] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Natural resistance of the male urethra to gonococci has not been explained by classical immune mechanisms but could result from antibacterial properties of urine. Accordingly, we measured survival in midmorning urine of 10(7) F-62 T2 gonococci per ml by serial dilutions and plate counts. Fifteen killer urines from eight people all killed greater than 3 logs (average, 5.3), and 13 of 15 were sterilized. Fourteen nonkiller (inhibitor) urines from seven subjects allowed no growth. Killer urines were more acidic (pH 5.4 versus 6.4) and more concentrated (861 versus 717 mosmol/kg) than nonkillers. Upon addition of hydrogen ion, urea, and sodium chloride to urines and broth, pH proved to be the major killing factor, but urea and NaCl were also bactericidal. Susceptibility to urine bactericidal power did not vary with colony type (T2 versus T4) or strain (F-62 versus two fresh isolates). Killing was rapid (0.5 to 3 h) and not bacteriolytic. Escherichia coli multiplied 10-fold in urines that inhibited growth of gonococci. Thus, the bacteriostatic effect of urine may explain why gonococci do not infect the bladder and kidney during gonorrhea. The bactericidal properties of urine may contribute to resistance against gonococcal urethritis.
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Pringle JR. Induction, selection, and experimental uses of temperature-sensitive and other conditional mutants of yeast. Methods Cell Biol 1975; 12:233-72. [PMID: 591 DOI: 10.1016/s0091-679x(08)60959-0] [Citation(s) in RCA: 26] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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Atlas RM, Bartha R. Inhibition by fatty acids of the biodegradation of petroleum. Antonie Van Leeuwenhoek 1973; 39:257-71. [PMID: 4541602 DOI: 10.1007/bf02578858] [Citation(s) in RCA: 35] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
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Borst-Pauwels GW, Dobbelmann J. The mechanism of inhibition of anaerobic phosphate uptake by fatty acids in yeast. BIOCHIMICA ET BIOPHYSICA ACTA 1972; 290:348-54. [PMID: 4565645 DOI: 10.1016/0005-2736(72)90077-6] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
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Borst-Pauwels GW, Huygen PL. Comparison of the effect of acidic inhibitors upon anaerobic phosphate uptake and dinitrophenol extrusion by metabolizing yeast cells. BIOCHIMICA ET BIOPHYSICA ACTA 1972; 288:166-71. [PMID: 4565498 DOI: 10.1016/0005-2736(72)90234-9] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
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Afting EG, Katsunuma T, Holzer H. Comparative studies on the inactivating enzymes for pyridoxal enzymes from yeast and rat. Biochem Biophys Res Commun 1972; 47:103-10. [PMID: 4554810 DOI: 10.1016/s0006-291x(72)80016-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
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