Past, present and future research directions with Pichia anomala

Abstract

The first International Pichia anomala Symposium provided a survey of past, recent and ongoing research on this yeast. The research community working with this yeast has focussed on several areas. Based on molecular data, a revision of the taxonomy is required: the name P. anomala is no longer applicable, as the genus Pichia is polyphyletic. The current debate centres on whether the yeast should be designated as Wickerhamomyces anomalus or if the previous name, Hansenula anomala, should be re-instated. The anti-microbial activities of this yeast received considerable attention during the symposium. H. anomala has been extensively studied as a biopreservation agent in many different post-harvest systems. Several mechanisms account for its anti-microbial activities, including the production of killer proteins and toxic volatile metabolites. Anti-idiotypic antibodies generating an "internal image" of a killer protein have been found to possess therapeutic activity against a broad range of microorganisms. A great diversity of H. anomala strains was reported at the symposium. Strains have been isolated from several food and feed systems and even from the intestine and reproductive organs of a malaria vector (Anopheles stephensi). Feed and food supplemented with certain H. anomala strains show an improved quality due, for example, to the addition of advantageous proteins and phytase activity. However, a number of apparent opportunistic pathogenic strains have also been isolated. Strain differentiation, especially the recognition of potentially pathogenic isolates, is an important challenge for the future commercialisation of this yeast. Future industrial and agricultural application of this yeast also raises questions of the economics of large-scale production, its survival during storage (formulation) and of safety regulations, all of which require further investigation.

Killer yeasts as biocontrol agents of spoilage yeasts and bacteria isolated from wine

“…These results demonstrate the biocontrol potential of these killer strains on spoilage yeasts, noting that P. guilliermondii Cd6 is an autochthonous strain from northwestern region of Argentina as Cf8 and Cf20 strains. These findings are in concordance with the literature, which express that killer toxins from S. cerevisiae have narrow inhibition spectra, while those belonging from W. anomalus often present broad inhibition spectra [8][9][10].…”

Growth Inhibition of Various Enterobacteriaceae Species by the Yeast Hansenula anomala during Storage of Moist Cereal Grain

“…The name Pichia anomala, used in recent years, does not reflect the phylogeny of this species. A new species name, Wickerhamomyces anomalus, has been proposed [9, 10], but some argue to reinstate the former name, H. anomala [20].) Interestingly, we recently found that H. anomala strongly inhibited E. coli and P. agglomerans in cereal grain (14).…”

Cultivo por lote de Wickerhamomyces anomalus en un biorreactor a escala laboratorio para la producción de una poligalacturonasa

“…4) indican que, en las condiciones de crecimiento, no hubo generación de ningún producto carbonado diferente a la biomasa y CO2. Según fue informado por otros autores, P. anomala (W. anomalus) es producida de manera eficiente considerando que es una levadura que presenta efecto Crabtree negativo, es decir que respira y produce biomasa en presencia de O2, independientemente de la concentración de azúcar presente en el medio (Passoth et al, 2011).…”

“…Una levadura pectinolítica fue aislada a partir de cásca-ras de frutas cítricas en la Provincia de Misiones, Argentina, la cual fue identificada como Wickerhamomyces anomalus, reclasificación de la especie Pichia anomala (Passoth et al, 2011). W. anomalus, al crecer en un medio de cultivo compuesto por Base Nitrogenada para Levaduras (Yeast Nitrogen Base, YNB), glucosa como fuente de carbono y energía (FCE) y pectina de citrus como inductor, excreta al medio una enzima con actividad poligalacturonasa (endo-PG, EC 3.2.1.15).…”