J. P. van der Walt

Fermentation of D-xylose to ethanol by a strain ofCandida shehatae

SummaryA strain ofCandida shehatae fermented 9% D-xylose directly to ethanol within 40 hours with a yield coefficient of 0.29. The specific rate of ethanol production attained a maximum value of 0.28 g ethanol (g cells h)−1. The aeration rate greatly influenced the fermentation parameters. The performance of this yeast compared favourably with the published data for other xylose-fermenting microorganisms.

A colour reaction for the differentiation of ascomycetous and hemibasidiomycetous yeasts

Seventy yeast strains, representative of twenty-six ascogenous genera, four saprobic hemibasidiomycetous genera and thirteen genera of the Cryptococcales were tested for their reaction with the stabilized aromatic diazonium compound, Diazonium Blue B salt. An aqueous, buffered solution of this compound gave a characteristic red colouration with the colonies of the hemibasidiomycetous species and those Cryptococcales characterized by the hemibasidiomycetous cell-wall type. The characteristic colour reaction was not observed with colonies of either the ascomycetous yeasts or those Cryptococcales characterized by the ascomycetous cell-wall type.The possible taxonomic use of the colour reaction with Diazonium Blue B salt as an affinitive characteristic is discussed.

Arxula gen. nov. (Candidaceae), a new anamorphic, arthroconidial yeast genus

The new genus Arxula is proposed for the classification of xerotolerant, ascomycetous, anamorphic, arthroconidial yeasts. The genus is considered to be of endomycetaceous affinity.

The wine yeast sf the cape

SummaryA method was developed for the recovery ofBrettanomyces species from materials heavily contaminated with other yeasts.This method was applied in the study of the occurrence of the genusBrettanomyces in the vinification process. It was found that these yeasts are not uncommon contaminants in the winery and on its equipment. These yeasts were, however, only recovered in one of ten industrial musts and could not be recovered from husks, pomace, or fresh grapes. This supports the view that the infection of wines and musts byBrettanomyces species is due to contamination spreading from latent foci of infection within the winery.

The yeast genus Yarrowia gen. nov.

The ascigerous teleomorph of Candida lipolytica (Harrison) Diddens et Lodder, previously classified as Endomycopsis lipolytica Wickerham et al. and as Saccharomycopsis lipolytica (Wickerham et al.) Yarrow, has been assigned to the new genus Yarrowia. Yarrowia lipolytica (Wickerham et al.) comb. nov. is the type species for the genus.The remaining species of Saccharomycopsis are revised.

Redefinition ofCandida Berkhout and the consequent emendation ofCryptococcus Kützing andRhodotorula Harrison

On the basis of affinitive charactersCandida has been restricted to anamorphs related to the Endomycetales. The excluded basidiomycetous anamorphs have been transferred to the emended generaRhodotorula andCryptococcus.

The wine yeasts of the Cape

In Part I of this series VAN DER WALT and VAN KERKEN (1958) found that species of the genus Brettanomyces were the most prevalent yeasts in South African wines showing yeast hazes. The present communication deals with the taxonomy of Brettanomyces strains isolated in this study. In a detailed study of the genus Brettanomyces CUSTERS (1940) first proved that these yeasts, which had previously been encountered only in beers, also occurred in wines. He identified ]~Iycotorula intermedia, a yeast isolated from French wine by KRUMBHOLZ and TAUSCHANOFF (1933) as a typical Brettanomyces species and considered it identical with Brettanomyces bruxellensis. BARRET, BIDAN and ANDRI~ (]955) similarly isolated strains of this genus from the yellow wines of the Ch~tteau Chalon, but regarded them as a variety of the above mentioned species, viz., Brett. bruxellensis var. vini. PEYNAUD and DOMERCQ (1956), on the other hand, compared the properties of several Brettanomyces strains, isolated from vinous products, with those of the type strains of Brett. bruxellensis, Brett. lambicus and Brett. clau.ssenii, and considered the differences sufficient to establish two new species, viz., Brett, vini and Brett. schanderlii. These workers limited their study of the biochemical properties of the yeasts to the fermentation and assimilation of five sugars,

Lodderomyces, a new genus of the Saccharomycetaceae

The yeast species previously described asSaccharomyces elongasporus Recca et Mrak has been transferred to the new genusLodderomyces. The diagnosis for the genus and standard description of its type species are given.

Kluyveromyces—A new yeast genus of theEndomycetales

SummaryA new budding yeast has been isolated from soil. Its most striking feature is the formation, generally preceded by isogamous or heterogamous conjugation, of unusually large multispored asci. The organism possesses a strong fermentative ability, fermenting glucose, galactose, saccharose and raffinose for one-third. Nitrate is not assimilated. It forms a pellicle in malt extract. A pseudomycelium is also formed. Cytological examination showed the vegetative cells to be uninucleate. The relationship which this yeast shows with theDipodascaceae and, in particular, withDipodascus uninucleatus Biggs, is discussed. For the classification of the yeast the new genusKluyveromyces was created. For the species the nameKluyveromyces polysporus is proposed. The Latin diagnosis of both the genus and the species is given.

The emendation of the genusKluyveromyces v. d. Walt

The genusKluyveromyces has been emended to include species forming 1 – 4 crescentiform, reniform, prolate ellipsoidal or spheroidal ascospores.Fourteen species have been assigned to the emended genusKluyveromyces.