Killer toxin from a novel killer yeastPichia kudriavzeviiRY55 with idiosyncratic antibacterial activity

Abstract

The killer phenomenon of yeast may have technological implications in many areas like beverage fermentation, food technology, biological control in agriculture, and in medicine. In the present study the killer phenomenon in Pichia kudriavzevii (P. kudriavzevii RY55) is being reported for the first time. The P. kudriavzevii RY55 toxin exhibited excellent antibacterial activity against several pathogens of human health significance such as Escherichia coli, Enterococcus faecalis, Klebsiella sp., Staphylococcus aureus, Pseudomonas aeruginosa and Pseudomonas alcaligenes. Killer toxin was purified to homogeneity by using ammonium sulphate precipitation and ion exchange chromatography and characterized for few properties. P. kudriavzevii RY55 killer toxin may be of vast significance in the development of novel antimicrobial chemotherapeutic agents, new bio-based safer candidates for food preservation and biocontrol, and starter cultures for fermentation industries.

Killer toxin from several food-derived Debaryomyces hansenii strains effective against pathogenic Candida yeasts

“…A cell-free preparation, it was consequently not subject to the physiological limitations of living D. hansenii, and initially showed high activity at all temperatures; however, as the time of incubation increased, activity decreased. That might be due to C. albicans and C. tropicalis outgrowing available mycocin molecules, or deactivation of mycocin with temperature and time of incubation (Bajaj et al, 2013); more likely, our crude preparation may contain additional components that degrade or inhibit the mycocin.…”

A novel killer protein from Pichia kluyveri isolated from an Algerian soil: purification and characterization of its in vitro activity against food and beverage spoilage yeasts

“…Several species of the genus Pichia have been reported to possess the killer character (Middelbeek et al 1979;Starmer et al 1992;Comitini et al 2004;Santos et al 2009;Polonelli et al 2011;Bajaj et al 2012); however, to the best of our knowledge, there are no studies reporting the ability of P. kluyveri to secrete killer proteins active against food and beverage spoilage yeasts. The present investigation describes a novel killer protein (Pkkp) from P. kluyveri, which exhibits a wide killing spectrum against a panel of food and beverage spoilage yeasts.…”

“…Their activity and stability are pH-and temperature-dependent: this potentially affects their successful applicability in food and beverage industry (Santos et al 2011). Accordingly, Pkkp was found to be active only at acidic pH values (3.0-5.0), with the optimal pH between 4.0 and 4.5, while the optimal temperature range was (20-30°C) with an optimum of 25°C, like to other killer proteins (Buzzini et al 2004;Comitini et al 2004;Bajaj et al 2012). Accordingly, Pkkp was found to be active only at acidic pH values (3.0-5.0), with the optimal pH between 4.0 and 4.5, while the optimal temperature range was (20-30°C) with an optimum of 25°C, like to other killer proteins (Buzzini et al 2004;Comitini et al 2004;Bajaj et al 2012).…”

Alternative Methods to SO2 for Microbiological Stabilization of Wine

“…Finally, killer yeasts may also inhibit wine-related, as well as human pathogenic, bacterial species (Bajaj et al, 2013;Meneghin, Reis, & Ceccato-Antonini, 2010;Oliva-Neto, Ferreira, & Yokoya, 2004). Some killer toxins have been shown to be active and stable at pH, temperature and nutritional conditions found in winemaking process, enough to cause sluggish or even stuck fermentations (Carrau, Neirotti, & Gioia, 1993;van Vuuren & Wingfield, 1986).…”