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1 Introduction One of the important sources of different types of microorganisms is traditional sourdough. The microbial ecosystem of sourdough contains safe lactic acid bacteria (LAB) and yeast strains

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In April 2011 the new 5th edition of “The Yeasts, a Taxonomic Study” was published (Kurtzman et al., 2011). This prompted to give an overview to orientate the interested readers about the substantial changes having carried out in the classification of yeasts since the previous 4th edition (Kurtzman & Fell, 1998). In terms of figures, the number of approved yeast species has increased from about 700 in 93 genera (4th ed.) to about 1500 in 148 genera (5th ed.), and within the overall figures, the ratio of basidiomycetous yeast genera increased from 39% to 42% (Table 1).

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Cereal Research Communications
Authors:
Doris Lucyshyn
,
Shamsozoha Abolmaali
,
Hanna Weindorfer
,
Mehrdad Shams
,
Gerlinde Wiesenberger
,
Eva Wilhelm
,
Marc Lemmens
, and
Gerhard Adam

Abolmaali, S., Mitterbauer, R., Spadiut, O., Peruci, M., Weindorfer, H., Lucyshyn, D., Ellersdorfer, G., Lemmens, M., Moll, W. D., Adam G. 2008. Engineered bakers yeast as a sensitive bioassay indicator organism

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, 240 ( 2000 ) [19] R. Schneiter and G. Daum , Extraction of Yeast Lipids . In: Yeast Protocols , Humana Press , Totowa, New Jersey , 2006

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Al-Tawaha, A. R. M. (2011) Effect of soil type and exogenous application of yeast extract on soybean seed isoflavones concentration. Int. J. Agric. Biol. 13 , 275

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Acta Alimentaria
Authors:
L. Červinka
,
P. Burg
,
I. Soural
,
V. Mašán
,
A. Čížková
,
J. Souček
,
V. Višacki
,
O. Ponjičan
, and
A. Sedlar

fermentation with emphasis on yeast as a complex microbiological process ( Ribéreau-Gayon et al., 2006a ). Fermentation can be spontaneous or controlled. Spontaneous alcoholic fermentation occurs with the action of non- Saccharomyces species. These are yeasts

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Acta Microbiologica et Immunologica Hungarica
Authors:
Johan Thevelein
,
Beatriz Bonini
,
Dries Castermans
,
Steven Haesendonckx
,
Johan Kriel
,
Wendy Louwet
,
Palvannan Thayumanavan
,
Yulia Popova
,
Marta Rubio-Texeira
,
Wim Schepers
,
Patrick Vandormael
,
Griet Zeebroeck
,
Peter Verhaert
,
Matthias Versele
, and
Karin Voordeckers

In yeast the Protein Kinase A (PKA) pathway can be activated by a variety of nutrients. Fermentable sugars, like glucose and sucrose, trigger a spike in the cAMP level, followed by activation of PKA and phosphorylation of target proteins causing a.o. mobilization of reserve carbohydrates, repression of stress-related genes and induction of growth-related genes. Glucose and sucrose are sensed by a G-protein coupled receptor system that activates adenylate cyclase and also activates a bypass pathway causing direct activation of PKA. Addition of other essential nutrients, like nitrogen sources or phosphate, to glucose-repressed nitrogen-or phosphate-starved cells, also triggers rapid activation of the PKA pathway. In these cases cAMP is not involved as a second messenger. Amino acids are sensed by the Gap1 transceptor, previously considered only as an amino acid transporter. Recent results indicate that the amino acid ligand has to induce a specific conformational change for signaling. The same amino acid binding site is involved in transport and signaling. Similar results have been obtained for Pho84 which acts as a transceptor for phosphate activation of the PKA pathway. Ammonium activation of the PKA pathway in nitrogen-starved cells is mediated mainly by the Mep2 transceptor, which belongs to a different class of transporter proteins. Hence, different types of sensing systems are involved in control of the yeast PKA pathway by nutrients.

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The ARTEMIS Global Antifungal Susceptibility Program provides the collection of epidemiological data and the results of the fluconazole and voriconazole susceptibility testing of yeast isolates. Participating in this study, a total of 7318 clinical yeast isolates were tested from different geographical areas in Hungary in the period 2001 to 2003. The species isolated most frequently was C. albicans (68.8%), followed by C. glabrata (11.8%), C. tropicalis (5.7%) and C. krusei (4.6%). Isolates of C. albicans, C. kefyr, C. lusitaniae, C. tropicalis and C. parapsilosis were highly susceptible to fluconazole (78.9-100%). The rates of isolation of fluconazole-resistant C. glabrata and C. krusei were higher in our study than the global mean in 2001 (28.2% and 87.5% vs. 18.3% and 70.2%, respectively). Differences were detected in the distribution of fluconazole-susceptibility data of C. glabrata isolates in the different counties of Hungary: most of the resistant isolates were observed in the eastern part of the country.

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The most important base material of the famous wine Tokaji Aszú is the noble rotted grapes attacked by Botrytis cinerea under special conditions. The objective of this study was to determine the quantitative and qualitative composition of the yeast and mould biota present on the surface of aszú-berries in the year of 2000 and 2001, and to compare these findings with the observations made in previous vintages. The studied years represented extremely different conditions for the noble rot, so the effect of the vintage on the quantitative and qualitative composition of the microflora was more pronounced than in the earlier years. The excellent year of 2000 resulted in yeast and mould counts (mean logarithmic values are of 4.47 and 4.72) significantly lower than found in the extremely poor vintage of 2001 (meanain values areof  6.58 for yeasts and 7.10 for total moulds). The place of sampling (vineyard or winery) had less impact on the quantitative composition of the microbiota, than found in in the formerprevious, less extreme years. The results of qualitative analysis, however, confirmed that the taxonomic composition of the yeast biota depends on the place of sampling, showing that the storage conditions of aszú grapes before vinification should be studied and optimized.

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Kluyveromyces marxianus cells as a source of β-D-galactosidase were employed for the production of lactose hydrolysed whole milk. The yeast cells were permeabilised to overcome the problem of enzyme extraction and poor permeability of cell membrane to lactose. To analyse and optimise the process variables for lactose hydrolysis, the experiments were conducted according to the Central Composite Rotatable Design (CCRD) using response surface methodology. The independent process variables for lactose hydrolysis were biomass concentration, temperature, agitation and incubation time. Statistical analysis of the results showed that, in the range studied, linear terms of biomass concentration, incubation time and process temperature had a significant effect (P<0.01) on lactose hydrolysis, however, the effect of agitation on lactose hydrolysis was significant when compared with stationery conditions. Numerical optimisation technique was applied to achieve the maximum possible lactose hydrolysis value. The optimum process conditions for lactose hydrolysis were 120 mg biomass (dry wt), 33.6 °C temperature, 105 r.p.m. agitation and 147 min of incubation time. Corresponding to these optimum conditions, the predicted value of lactose hydrolysis was found to be 88.6%, which was experimentally verified.

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