Isolation and Characterization of Yeasts for Detoxification of Aflatoxin

Deepak, M. B. (2015) Isolation and Characterization of Yeasts for Detoxification of Aflatoxin. PhD thesis, University of Mysore.

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Abstract

The aflatoxins are ubiquitous contaminates of the human food supply throughout the economically developing world. The adverse toxicological consequences of these compounds in populations are quite varied owing to a wide range of exposures that lead to acute effects, including rapid death and chronic outcomes, such as hepatocellular carcinoma, high hepatitis B virus infection rate etc. To avoid these problems natural biocontrol strategies need to be implemented to avoid toxicity in humans and animals. Yeasts / yeast cell wall is the best substances to use detoxification of aflatoxin. Yeasts, as an inevitable part of the microflora of various fermented foods and beverages, are found in a wide range of foods from plant or animal origin, where they have a significant impact on food safety and organoleptic properties. They provide vitamin B, proteins, peptides, amino-acids and make trace minerals biological available. Regardless of their non-human origin, such nonpathogenic yeasts fulfil the major criteria for probiotic definition. Interest in probiotic yeasts has increased, especially in relation to animal feed but also for human applications. The present study is to screen for aflatoxin binding Non Saccharomyces yeast strains. This is in view to understand, whether food borne strains of yeast species possess aflatoxin binding properties. This would be of fundamental importance in developing, understanding and handling of new potential bio-therapeutic agents, or feed additive for the (functional) food / feed industry. A number of fermented foods were screened with a view to isolate yeasts having aflatoxin binding capabilities. The promising yeasts were identified as Pichia manshurica isolate H4S7K13, Saccharomyces cerevisiae strain Y5-3, Saccharomyces cerevisiae strain MUCL 51248. Among the isolates non-Saccharomyces Pichia manshurica was found to be effective in aflatoxin binding and the same organism was fed to wistar albino weanling rats with and without toxin AFB1 after thirty days. The biochemical parameters indicated that the isolate Pichia manshurica exhibited similar mycotoxin protective character like that of Saccharomyces cerevisiae. This indicated that Saccharomyces is not only organism which can be used for mycotoxin decontamination in food and feed. To our knowledge this is first report where non-Saccharomyces form have been used for decontamination of mycotoxin AFB1, and also our earlier experiments proved that Pichia anomala, Clavispora lusitaniae and Candida tropicalis also have toxin binding properties. We feel this work will open up similar kind of work and test large number of organisms, which are part of the fermentation consortium.

Item Type:	Thesis (PhD)
Uncontrolled Keywords:	aflatoxins, Yeasts, detoxification
Subjects:	600 Technology > 08 Food technology > 10 Food Microorganisms 600 Technology > 08 Food technology > 29 Microbiological food > 04 Yeast
Divisions:	Food Microbiology
Depositing User:	Food Sci. & Technol. Information Services
Date Deposited:	19 May 2016 05:26
Last Modified:	19 May 2016 05:26
URI:	http://ir.cftri.res.in/id/eprint/12169

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