Production and Optimization of Killer Toxin in Debaryomyces hansenii Strains

Çorbacı, Cengiz; Uçar, Füsun

doi:10.1590/1678-4324-2017160339

Cited by 13 publications

(4 citation statements)

References 30 publications

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“…The results showed decreasing of coliform bacteria count for all treatments in the Monterey cheese during the ripening period to zero after 14 days of ripening, this may be due to the ripening conditions and production of bacteriocin, lactic acid and acetic acid by the starter bacteria, as well as the production of lethal toxins from yeast in a pH ranging from 3-6, destroyed Pathogenic microorganisms such as coliform bacteria (19). Fig.…”

Section: Fig (3) Coliform Bacteria Count In Monterey Cheese Treated mentioning

confidence: 85%

Role of Debaryomyces hansenii yeast in improving the microbial and sensory properties of Monterey cheese

Al-Zobaay

Alzobaay

2018

AJVS

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Debaryomyces hansenii yeast was grown in Malt Extract Broth medium at 30 °C for 5 days until the total count reached 5.6 ×108 colony forming units/ milliliter, Monterey cheese was made from cow's milk and adding of starter bacteria Lactococcus lactis subsp. lactis and Lactococcus lactis subsp.cremoris with D.hansenii yeast as adjunct starter in 2% for each treatment included M1 (100% starter bacteria), M2 (50% starter bacteria + 50% live D.hansenii) and M3 (50% starter bacteria + 50% dead D.hansenii),the ripening of Monterey cheese was done at 15°C and (85% relative humidity) for 56 days. The highest count of starter bacteria was 9.7 ×108 cfu/g in M1 treatment after 3 days of ripening, the lowest number of starter bacteria was 6.9 ×108 cfu/g in M2 treatment. The highest count of D.hansenii yeast was 4.3 x108 cfu/g after 3 days of ripening in M2 treatment, while the lowest count was 2.6 ×108 cfu/g in the same treatment after 56 days of ripening, no yeast was found in the treatments that had dead yeast cells, all treatments under study were decreased in the total count of coliform bacteria, Staphylococcus aureus and psychrotrophic bacteria after 14 days as they were within the standard specifications of these groups of microorganisms, Then reached to zero in the late time of ripening. M2 showed the best results of sensory evaluation in taste, flavor, textures, color and bitterness after 56 days of ripening.

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Section: Fig (3) Coliform Bacteria Count In Monterey Cheese Treated mentioning

confidence: 85%

Role of Debaryomyces hansenii yeast in improving the microbial and sensory properties of Monterey cheese

Al-Zobaay

Alzobaay

2018

AJVS

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“…In addition, the loss of immunity of D. hansenii strains to its own toxin due to the loss of linear plasmids was also not observed, neither at pH 4.6 nor 7 ( Figure S10 ). The killer effect of the studied strains on Y. lipolytica and P. roqueforti was observed at pH 4.6, which is optimal for killer toxin activity of D. hansenii strains isolated from cheese [ 39 , 42 , 86 ]. However, no difference in lethal activity between VLEs possessing and cured of them isolates could be noted ( Figures S11 and S12 ).…”

Section: Resultsmentioning

confidence: 99%

New Cytoplasmic Virus-Like Elements (VLEs) in the Yeast Debaryomyces hansenii

Połomska

Neuvéglise

Zyzak

et al. 2021

Toxins

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Yeasts can have additional genetic information in the form of cytoplasmic linear dsDNA molecules called virus-like elements (VLEs). Some of them encode killer toxins. The aim of this work was to investigate the prevalence of such elements in D. hansenii killer yeast deposited in culture collections as well as in strains freshly isolated from blue cheeses. Possible benefits to the host from harboring such VLEs were analyzed. VLEs occurred frequently among fresh D. hansenii isolates (15/60 strains), as opposed to strains obtained from culture collections (0/75 strains). Eight new different systems were identified: four composed of two elements and four of three elements. Full sequences of three new VLE systems obtained by NGS revealed extremely high conservation among the largest molecules in these systems except for one ORF, probably encoding a protein resembling immunity determinant to killer toxins of VLE origin in other yeast species. ORFs that could be potentially involved in killer activity due to similarity to genes encoding proteins with domains of chitin-binding/digesting and deoxyribonuclease NucA/NucB activity, could be distinguished in smaller molecules. However, the discovered VLEs were not involved in the biocontrol of Yarrowia lipolytica and Penicillium roqueforti present in blue cheeses.

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“…The killing activity of the most well-studied toxin K1 is based on binding to the β-1,6-D-glucan on a target cell and disruption of cytoplasmic membrane by forming the cation-selective ion channels (Gier et al, 2020). Dairy isolates of D. hansenii produced mycocins, targeting Y. lipolytica, Wickerhamomyces anomalus, C. tropicalis, and C. albicans (Banjara et al, 2016;Al-Qaysi et al, 2017;Çorbacı and Uçar, 2017). Studies with C. albicans mutants defective in MAPK kinase pathways suggested that, specifically Hog1 phosphorylation site and the kinase activity, were implicated in the resistance of C. albicans to D. hansenii killer toxins (Morales-Menchén et al, 2018).…”

Section: Other Microbial Yeast Interactionsmentioning

confidence: 99%

Occurrence of Yeasts in White-Brined Cheeses: Methodologies for Identification, Spoilage Potential and Good Manufacturing Practices

et al. 2020

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Yeasts are generally recognized as contaminants in the production of white-brined cheeses, such as Feta and Feta-type cheeses. The most predominant yeasts species are Debaryomyces hansenii, Geotrichum candidum, Kluyveromyces marxianus, Kluyveromyces lactis, Rhodotorula mucilaginosa, and Trichosporon spp. Although their spoilage potential varies at both species and strain levels, yeasts will, in case of excessive growth, present a microbiological hazard, effecting cheese quality. To evaluate the hazard and trace routes of contamination, the exact taxonomic classification of yeasts is required. Today, identification of dairy yeasts is mainly based on DNA sequencing, various genotyping techniques, and, to some extent, advanced phenotypic identification technologies. Even though these technologies are state of the art at the scientific level, they are only hardly implemented at the industrial level. Quality defects, caused by yeasts in white-brined cheese, are mainly linked to enzymatic activities and metabolism of fermentable carbohydrates, leading to production of metabolites (CO 2 , fatty acids, volatile compounds, amino acids, sulfur compounds, etc.) and resulting in off-flavors, texture softening, discoloration, and swelling of cheese packages. The proliferation of spoilage yeast depends on maturation and storage conditions at each specific dairy, product characteristics, nutrients availability, and interactions with the co-existing microorganisms. To prevent and control yeast contamination, different strategies based on the principles of HACCP and Good Manufacturing Practice (GMP) have been introduced in white-brined cheese production. These strategies include milk pasteurization, refrigeration, hygienic sanitation, air filtration, as well as aseptic and modified atmosphere packaging. Though a lot of research has been dedicated to yeasts in dairy products, the role of yeast contaminants, specifically in white-brined cheeses, is still insufficiently understood. This review aims to summarize the current knowledge on the identification of contaminant yeasts in white-brined cheeses, their occurrence and spoilage potential related to different varieties of white-brined cheeses, their interactions with other microorganisms, as well as guidelines used by dairies to prevent cheese contamination.

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Production and Optimization of Killer Toxin in Debaryomyces hansenii Strains

Abstract: Postharvest diseases of fruits and vegetables result in critical losses

Cited by 13 publications

References 30 publications

Role of Debaryomyces hansenii yeast in improving the microbial and sensory properties of Monterey cheese

Role of Debaryomyces hansenii yeast in improving the microbial and sensory properties of Monterey cheese

New Cytoplasmic Virus-Like Elements (VLEs) in the Yeast Debaryomyces hansenii

Occurrence of Yeasts in White-Brined Cheeses: Methodologies for Identification, Spoilage Potential and Good Manufacturing Practices

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