Identification and killer activity of a yeast contaminating starter cultures ofSaccharomyces cerevisiaestrains used in the Turkish baking industry

1997 ◽  
Vol 14 (2) ◽  
pp. 125-131 ◽  
Author(s):  
F. Izgü ◽  
D. Altınbay ◽  
A. Yüceliş
Keyword(s):  
Starter Cultures ◽  
Killer Activity ◽  
Baking Industry

scholarly journals Dynamic modelling of the killing mechanism of action by virus-infected yeasts

2019 ◽  
Vol 16 (152) ◽  
pp. 20190064
Author(s):  
Sean Sheppard ◽  
Duygu Dikicioglu
Keyword(s):  
Large Scale ◽  
Mechanistic Model ◽  
Dynamic Modelling ◽  
Starter Cultures ◽  
Apoptotic Pathway ◽  
Toxic Activity ◽  
Killer Activity ◽  
Killer Yeasts ◽  
Death Kinetics ◽  
Kinetics Of

Killer yeasts are microorganisms, which can produce and secrete proteinaceous toxins, a characteristic gained via infection by a virus. These toxins are able to kill sensitive cells of the same or a related species. From a biotechnological perspective, killer yeasts are beneficial due to their antifungal/antimicrobial activity, but also regarded as problematic for large-scale fermentation processes, whereby those yeasts would kill starter cultures species and lead to stuck fermentations. Here, we propose a mechanistic model of the toxin-binding kinetics pertaining to the killer population coupled with the toxin-induced death kinetics of the sensitive population to study toxic action. The dynamic model captured the transient toxic activity starting from the introduction of killer cells into the culture at the time of inoculation through to induced cell death. The kinetics of K1/K2 activity via its primary pathway of toxicity was 5.5 times faster than its activity at low concentration inducing the apoptotic pathway in sensitive cells. Conversely, we showed that the primary pathway for K28 was approximately three times slower than its equivalent apoptotic pathway, indicating the particular relevance of K28 in biotechnological applications where the toxin concentration is rarely above those limits to trigger the primary pathway of killer activity.

scholarly journals Understanding the killing mechanism of action by virus-infected yeasts

2018 ◽  
Author(s):  
Sean Sheppard ◽  
Duygu Dikicioglu
Keyword(s):  
Large Scale ◽  
Deterministic Model ◽  
Mechanistic Model ◽  
Starter Cultures ◽  
Apoptotic Pathway ◽  
Toxic Activity ◽  
Killer Activity ◽  
Killer Yeasts ◽  
Death Kinetics ◽  
Kinetics Of

AbstractKiller yeasts are microorganisms, which can produce and secrete proteinaceous toxins, a characteristic gainedviainfection by a virus. These toxins are able to kill sensitive cells of the same or a related species. From a biotechnological perspective, killer yeasts have been considered as beneficial due to their antifungal/antimicrobial activity, but also regarded as problematic for large-scale fermentation processes, whereby those yeasts would kill species off starter cultures and lead to stuck fermentations. Here, we propose a mechanistic model of the toxin-binding kinetics pertaining to the killer population coupled with the toxin-induced death kinetics of the sensitive population to study toxic actionin silico. Our deterministic model explains how killerSaccharomyces cerevisiaecells distress and consequently kill the sensitive members of the species, accounting for the K1, K2 and K28 toxin mode of action at high or low concentrations. The dynamic model captured the transient toxic activity starting from the introduction of killer cells into the culture at the time of inoculation through to induced cell death, and allowed us to gain novel insight on these mechanisms. The kinetics of K1/K2 activityviaits primary pathway of toxicity was 5.5 times faster than its activity at low concentration inducing the apoptotic pathway in sensitive cells. Conversely, we showed that the primary pathway for K28 was approximately 3 times slower than its equivalent apoptotic pathway, indicating the particular relevance of K28 in biotechnological applications where the toxin concentration is rarely above those limits to trigger the primary pathway of killer activity.

scholarly journals Properties of Starter Cultures Based on Non-Traditional Flours

2021 ◽  
pp. 470-479
Author(s):  
Sergey Gur'ev ◽  
Vitaly Popov
Keyword(s):  
Inflation Rate ◽  
Reducing Sugars ◽  
Starter Cultures ◽  
Bakery Products ◽  
Microbial Composition ◽  
Fermentation Time ◽  
Lentil Flour ◽  
The Difference ◽  
Baking Industry ◽  
Buckwheat Flour

Introduction. Bread and bakery products contain nutritional components that make an integral part of human diet. Starter cultures are a promising way to prepare bakery products. The research objective was to study the effect of non-traditional flours and their wheat mixes on the activity, sensory, and physicochemical properties of starter cultures. Study objects and methods. The research featured Lesaffre starter cultures (Saf-Levain LV1 and Saf-Levain LV4) with lentil flour and green buckwheat flour. It involved organoleptic, titrimetric, and photocolorimetric methods, as well as the “ball surfacing” method, to determine the fermentation activity of starter cultures and to assess the changes in their volume. The acid content of the flour was determined by titrating the aqueous solution of the sample. The amount of reducing sugars was determined by the photocolorimetric method based on the interaction of carbonyl groups of sugars in an alkaline medium with copper glycerate; the optical density of the resulting solution was performed using a photoelectrocolorimeter. The change in the volume of the starter cultures was determined by a non-standard method of using measuring cups in the process of thermostating. The research also included a sensory evaluation of the semi-finished products. Results and discussion. Green buckwheat flour had a positive effect on the activity of starter cultures based on Saf-Levain LV4 and LV1. The sensory properties of starter cultures with non-traditional flours differed from the control samples in aroma, taste, appearance, and inflation rate. The acidity of the samples varied depending on the flour, its quantity, and the starting culture. The greatest accumulation of acids occurred in the sample with 50% of green buckwheat flour and the samples with 25 and 50% of lentil flour. The most intense reduction in the amount of reducing sugars was observed in the samples with 25 and 50% of green buckwheat flour (from 1.9 to 3.9 times, depending on the sample). In the samples with lentil flour, it was 75 and 100% (from 2.7 to 7.5 times, depending on the sample). The difference in the samples with LV1 was greater than in the samples with LV4, which can be explained by the differences in their microbial composition. The inflation rate was higher in the test samples than in the control. Conclusion. The resulting starter cultures can be recommended for baking industry and further research. Starter cultures based on non-traditional flours will eventually reduce the fermentation time and produce bakery products with high consumer properties. The non-traditional flours can expand the range of bakery products and increase their nutritional value.

scholarly journals Purification and Characterization of WA18, a New Mycocin Produced by Wickerhamomyces anomalus Active in Wine Against Brettanomyces bruxellensis Spoilage Yeasts

2020 ◽  
Vol 9 (1) ◽  
pp. 56
Author(s):  
Francesca Comitini ◽  
Alice Agarbati ◽  
Laura Canonico ◽  
Edoardo Galli ◽  
Maurizio Ciani
Keyword(s):  
Competitive Inhibition ◽  
Receptor Site ◽  
Restriction Enzymes ◽  
Culture Conditions ◽  
Starter Cultures ◽  
Cell Wall Polysaccharides ◽  
Brettanomyces Bruxellensis ◽  
Killer Activity ◽  
Wickerhamomyces Anomalus ◽  
Spoilage Yeasts

Wickerhamomyces anomalus strain 18, isolated from a natural underground cheese ripening pit, secretes a mycocin named WA18 that inhibits wine spoilage yeasts belonging to Brettanomyces bruxellensis species, with a broad-spectrum of activity. WA18 was purified, and the purified protein was digested with specific restriction enzymes (lysine K and arginine R cut sites). The LC–MS and LC–MS/MS analysis after enzymatic digestions revealed a molecular weight of 31 kDa. Bioinformatics processing and database research of digested pure killer protein showed 99% identity with a UDP-glycosyltransferase protein. Competitive inhibition assay of killer activity by cell-wall polysaccharides suggests that branched glucans represent the first receptor site of the toxin on the envelope of the sensitive target. The WA18 partially purified crude extract (PPCE) showed high stability of antimicrobial activity at the physicochemical conditions suitable for the winemaking process. Indeed, in wine WA18 was able to counteract B. bruxellensis and control the production of ethyl phenols. In addition, the strain WA18 was compatible with Saccharomyces cerevisiae in co-culture conditions with a potential application together with commercial starter cultures. These data suggest that WA18 mycocin is a promising biocontrol agent against spoilage yeasts in winemaking, particularly during wine storage.

Development of biotechnology for gluten-free sourdough bakery products with a new microbial composition

2020 ◽  
Vol 29 (12) ◽  
pp. 59-63
Author(s):  
O.I. Parakhina ◽  
◽  
M.N. Lokachuk ◽  
L.I. Kuznetsova ◽  
E.N. Pavlovskaya ◽  
...  
Keyword(s):  
Lactic Acid ◽  
Lactic Acid Bacteria ◽  
Starter Culture ◽  
Comparative Assessment ◽  
Starter Cultures ◽  
Bakery Products ◽  
Gluten Free ◽  
Microbial Composition ◽  
Fermentative Activity ◽  
Theoretical Foundations

The research was carried out within the framework of the theme of state assignment № 0593–2019–0008 «To develop theoretical foundations for creating composite mixtures for bakery products using physical methods of exposure that ensure homogeneity, stability of mixtures and bioavailability of nutrients, to optimize diets population of Russia». The data on the species belonging of new strains of lactic acid bacteria and yeast isolated from samples of good quality gluten-free starter cultures are presented. A comparative assessment of the antagonistic and acid-forming activity of strains of lactic acid bacteria and the fermentative activity of yeast was carried out. The composition of microbial compositions from selected strains of LAB and yeast was developed. The influence of the starter culture on the new microbial composition on the physicochemical, organoleptic indicators of the bread quality and resistance to mold and ropy-disease was investigated.

First reported case of Weissella confusa abundance in the lung microbiota of a critically ill trauma patient with acute respiratory distress syndrome - caution warranted in the use of the Weissella genus as a probiotic

2020 ◽  
Author(s):  
Sandeep Chakraborty
Keyword(s):  
Acute Respiratory Distress Syndrome ◽  
Respiratory Distress Syndrome ◽  
Respiratory Distress ◽  
Critically Ill ◽  
Distress Syndrome ◽  
Joint Infection ◽  
Starter Cultures ◽  
Trauma Patients ◽  
Virulence Determinants ◽  
Prosthetic Joint

Weissella strains are currently being used for biotechnological and probiotic purposes [1]. While, Weissella hellenica found in flounder intestine had probiotic effects [2], certain species from this genus are opportunistic pathogens in humans. Apart from being implicated in disease in farmed rainbow trout [3], Weissella has been found to cause the following disease in humans.1. endocarditis [4,5]2. bacteraemia [6]3. prosthetic joint infection [7]Whole genome sequences ‘find several virulence determinants such as collagen adhesins, aggregation sub- stances, mucus-binding proteins, and hemolysins in some species’, as well as antibiotic resistance-encoding genes [8]. Caution is warranted in selecting of Weissella strains as starter cultures or probiotics, if at all, since the other option, Lactobacillus, are rarely involved in human disease.Here, the analysis of the lung microbiota in critically ill trauma patients suffering from acute respiratory distress syndrome [9] shows (Accid:ERR1992912) shows complete colonization of Weissella (Fig 1). While, the study mentions ‘significant enrichment of potential pathogens including Streptococcus, Fusobacterium, Prevotella, Haemophilus and Treponema’, there is no reference to the Weissella genus. The percentages of Weissella strains are :confusa=81, soli=7 ,hellenica=5 ,diestrammenae=2. I believe this is the first reported case of Weissella causing ARDS in humans.

Isolating lactic starter cultures with antimicrobial activity for sourdough processes

Food Control ◽  
2006 ◽  
Vol 17 (4) ◽  
pp. 263-270 ◽  
Author(s):  
Ömer Şimşek ◽  
Ahmet Hilmi Çon ◽  
Şener Tulumogˇlu
Keyword(s):  
Antimicrobial Activity ◽  
Starter Cultures
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