Wickerhamiella shivajii sp. nov., a thermotolerant yeast isolated from distillery effluent.

Abstract

Ethanol production at high temperatures has garnered much interest in recent years and a key factor is the availability of thermotolerant yeasts. During an investigation on the diversity of thermotolerant yeasts from different habitats, a novel yeast species from the spent wash of a distillery unit associated with a sugar factory was isolated. Phylogenetic analysis of D1/D2 large subunit and ITS rRNA genes placed this species in the ascomycetous genus Wickerhamiella. The novel species can be distinguished from the closely related species Wickerhamiella pararugosa using these rRNA gene regions. The cells of the new species are ovoid to ellipsoid with a diameter of 3.5-6.0×2.4-3.10 µm, while W. pararugosa cells are cylindrical with a cell diameter of 1.5-3.0×6-23 µm. This novel species represents, together with Wickerhamiella cacticola, one of the two most thermotolerant yeast species in the genus Wickerhamiella, able to grow at 42 °C. Wickerhamiella shivajii sp. nov. is proposed during this study.