Screening and Extracting Mycocin Secreted by Yeast Isolated from Koumiss and Their Antibacterial Effect

Abstract

Koumiss is a common fermented mare's milk with beneficial therapeutic effects on cardiovascular disease, tuberculosis, and diarrhea. The mare's milk is fermented by lactic acid bacteria (LAB) and yeasts. Although information about LAB from Koumiss is comprehensive, there is limited knowledge about yeasts from Koumiss and their effects. The purpose of this study was to screen and extract mycocin secreted by yeast isolated from Koumiss and test their antibacterial effect against pathogenic Escherichia coli, The yeasts from Koumiss were isolated and those producing mycocin were screened by the Oxford cup method. Crude extracts of mycocin were then extracted by ethyl acetate, and temperature stabilities of them were investigated. The crude extracts of mycocin were tested against pathogenic E. coli and compared both in vivo and in vitro. Three Saccharomyces cerevisiae, and two Kluyveromyces marxianus were isolated from Koumiss in Inner Mongolia. All these yeasts produced mycocin. The two crude extracts of mycocin secreted by K. marxianus were active and stable at temperatures between 25°C and 45°C. They had better antibacterial effect in vitro and in vivo and were shown to be effective in preventing E. coli disease in mice. It may be possible to use crude extracts of mycocin secreted by yeast isolated from Koumiss to inhibit the growth of E. coli.

Bioprotective Role of Yeasts

“…Moreover, Hatoum et al [ 71 ] characterized anti-listerial hydrophobic peptides, extracted from four dairy yeast cultures identified as D. hansenii , Pichia fermentans , Candida tropicalis and Wickerhamomyces anomalus , which induced leakage in bacterial cells and ultimately caused bacterial lysis. More recently, Chen and co-workers [ 72 ] isolated two strains of Kluyveromyces marxianus producing mycocins from Koumiss in Inner Mongolia and demonstrated that the two crude extracts were effective at preventing Escherichia coli disease in mice. Finally, a very recent study, aimed at evaluating some probiotic properties of the P. pastoris strain X-33 wild-type, demonstrated the growth inhibition of Salmonella typhimurium in vitro and the reduction of bacterial adhesion to the human colorectal cancer HCT-116 cells [ 73 ].…”

Antimicrobial activity of Wickerhamomyces anomalus mycocins against strains of Staphylococcus aureus isolated from meats

“…This killer toxin are secondary metabolites (enzymes), of a protein or glycoprotein nature with antibiotic activity, as they cause disturbance in the cell wall of the pathogen and cause deleterious effects (Comitini et al, 2004). Other studies have identified the same potential in yeasts of the genera Debaryomyces, Pichia, Kluyveromyces, Wickerhamomyces, Williopsis and Zygosaccharomyces among others (Ceugniez et al, 2015;Chen et al, 2015;França et al, 2015;Hatoum et al, 2012;Passoth et al, 2011;Seddik et al, 2016).…”

Effects of antibacterial compound of Saccharomyces cerevisiae from koumiss on immune function and caecal microflora of mice challenged with pathogenic Escherichia coli O8

“…Among these strains, E. coli O8 was the dominant pathogenic strain (Simujide et al 2012). In addition, we found that an antibacterial compound of S. cerevisiae from koumiss could inhibit the growth of pathogenic E. coli O8 in vitro (Chen et al 2015). It is expected to become a new antibiotic substitute.…”

“…A total of 96 mice of the Kunming strain obtained from the Animal Centre of Inner Mongolia University, Hohhot, China, weighing 18-22 g were randomly divided into 3 groups of 32 mice each. The experimental design is presented in Table 1 (Chen et al 2015). Mice in each group were reared in conventional cages (545 × 395 × 200 mm) with sawdust maintained at a constant temperature (22 ± 1 °C) with a 12-h light/dark cycle.…”