Potential of Two Metschnikowia pulcherrima (Yeast) Strains for In Vitro Biodegradation of Patulin
Agroinnova, Centre of Competence for the Innovation in the Agro-Environmental Sector, Universita degli Studi di Torino, via L. da Vinci 44, 10095 Grugliasco, Torino, Italy. Journal of food protection
(Impact Factor: 1.85).
01/2011; 74(1):154-6. DOI: 10.4315/0362-028X.JFP-10-331
Patulin contamination of apple and other fruit-based foods and beverages is an important food safety issue, as consumption of these commodities throughout the world is great. Studies are therefore necessary to reduce patulin levels to acceptable limits or undetectable levels to minimize toxicity. This study was undertaken to investigate the efficacy of two Metschnikowia pulcherrima strains (MACH1 and GS9) on biodegradation of patulin under in vitro conditions. These yeast strains were tested for their abilities to degrade patulin in liquid medium amended with 5, 7.5, 10, and 15 μg/ml patulin and a yeast cell concentration of 1 × 10(8) cells per ml at 25°C. Of the two strains tested, MACH1 completely (100%) reduced patulin levels within 48 h, and GS9 within 72 h, at all concentrations of patulin. MACH1 effectively degraded the patulin within 24 h by 83 to 87.4%, and GS9 by 73 to 75.6% at 48 h, regardless of concentration. Patulin was not detected in yeast cell walls. This indicates that yeast cell walls did not absorb patulin, and that they completely degraded the toxin. Patulin had no influence on yeast cell concentration during growth. Therefore, these yeast strains could potentially be used for the reduction of patulin in naturally contaminated fruit juices. To our knowledge, this is the first report regarding the potential of M. pulcherrima strains for patulin biodegradation.
Available from: Davide Spadaro
- "Some components of the microbial community present on the surface of fruit and vegetables, such as bacteria and yeasts, have been shown to have significant antagonistic activity against P. expansum (Usall et al., 2001; Janisiewicz and Korsten, 2002). Different yeasts are also able to reduce the patulin level in vitro (Coelho et al., 2008; Reddy et al., 2011). Fermentative yeasts reduce patulin contamination during production of cider from apple juice (Harwig et al., 1973). "
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ABSTRACT: The efficacy of three antagonistic yeasts, Metschnikowia pulcherrima strain MACH1, M. pulcherrima strain GS9, and Metschnikowia fructicola strain AL27, against Penicillium expansum and patulin accumulation was evaluated on apples stored at room (22 ± 1 °C for 7 days) and cold temperatures (1 ± 1 °C for 56 days). To increase the potential range of application of the biocontrol agents (BCAs), their efficacy was evaluated on four cultivars of apple, i.e. ‘Golden Delicious’, ‘Granny Smith’, ‘Red Chief’ and ‘Royal Gala’. AL27 was more effective than MACH1 and GS9 in the control of blue mold rot and in the reduction of patulin accumulation. The efficacy of AL27 was in most cases similar to the chemical control used, making the antagonist as competitive as chemical fungicides. In vitro experiments showed that AL27 reduced the conidial germination and germ tube length of P. expansum more than the other strains. The three BCAs were more effective in the control of blue mold rot on ‘Golden Delicious’ apples than on the other tested cultivars.
Postharvest Biology and Technology 01/2013; 75:1-8. DOI:10.1016/j.postharvbio.2012.08.001 · 2.22 Impact Factor
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ABSTRACT: There is a worldwide trend to understand the impact of non-Saccharomyces yeast species on the process of winemaking. Although the predominant species at the end of the fermentation is Saccharomyces cerevisiae, several non-Saccharomyces species present during the first days of the process can produce and/or release aromas that improve the bouquet and complexity of the final wine. Since no genomic sequences are available for the predominant non-Saccharomyces species selected from grapes or musts (Hanseniaspora uvarum, Hanseniaspora vineae, Hanseniaspora opuntiae, Metschnikowia pulcherrima, Candida zemplinina), a reproducible PCR method was devised to discriminate strains at the subspecies level. The method combines different oligonucleotides based on tandem repeats with a second oligonucleotide based on a conserved tRNA region, specific for ascomycetes. Tandem repeats are randomly dispersed in all eukaryotic genomes and tRNA genes are conserved and present in several copies in different chromosomes. As an example, the method was applied to discriminate native M. pulcherrima strains but it could be extended to differentiate strains from other non-Saccharomyces species. The biodiversity of species and strains found in the grape ecosystem is a potential source of new enzymes, fungicides and/or novel sustainable methods for biological control of phytopathogens.
Applied Microbiology and Biotechnology 11/2011; 93(2):807-14. DOI:10.1007/s00253-011-3714-4 · 3.34 Impact Factor
Available from: Ksenija Markov
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ABSTRACT: Fungicides are the most common agents used in postharvest treatment of fruit and are the most effective against blue mould, primarily caused by Penicillium expansum. Alternatively, blue mould can be treated with antagonistic microorganisms naturally occurring on fruit, such as the bacterium Gluconobacter oxydans. The aim of this study was to establish the antifungal potential of the G. oxydans 1J strain isolated from apple surface against Penicillium expansum in culture and apple juice and to compare it with the efficiency of a reference strain G. oxydans ATCC 621H. The highest antifungal activity of G. oxydans 1J was observed between days 3 and 9 with no colony growth, while on day 12, P. expansum colony diameter was reduced to 42.3 % of the control diameter. Although G. oxydans 1J did not fully inhibit mould growth, it showed a high level of efficiency and completely prevented patulin accumulation in apple juice.
Archives of Industrial Hygiene and Toxicology 06/2013; 64(2):93-98. DOI:10.2478/10004-1254-64-2013-2308 · 0.93 Impact Factor
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