Hanseniaspora meyeri

Lore & Background

The first isolated sample of Hanseniaspora meyeri was obtained from the fruit of a soapberry plant in Hawaii. Its specific epithet 'meyeri' honors Piet Meyer, a young South African scientist. Genetic sequencing shows the species is very closely related to Hanseniaspora clermontiae.

Microscopic examination in YM liquid medium after 48 hours at 25 °C reveals cells that are 2.5 to 12.5 μm by 1.5 to 6.0 μm, apiculate, ovoid to elongate, appearing singly or in pairs. Reproduction is by budding at both poles. In broth culture, sediment is present, and after one month a very thin ring forms. Colonies on malt agar after one month at 25 °C appear cream-colored, butyrous, glossy, and smooth, with flat to slightly raised centers and entire to slightly undulating margins. The yeast forms poorly-developed pseudohyphae on cornmeal or potato agar and produces two to four hat-shaped ascospores after at least two weeks on 5% Difco malt extract agar.

It can ferment glucose and cellobiose, but not galactose, sucrose, maltose, lactose, raffinose or trehalose. It has positive growth at 30 °C but no growth at 35 °C. It can grow on agar containing 0.1% cycloheximide and 10% sodium, but growth on 50% glucose-yeast extract agar is weak. It can grow on media with 2-Keto-d-gluconate as a sole carbon source.

Reader's Guide

Hanseniaspora meyeri is significant as a species with a broad ecological range, having been isolated from diverse substrates including flowers, fruit flies, stem rot, and spoiled grape punch across multiple continents. Its discovery in Hawaii from a soapberry fruit, and subsequent isolations from Georgia (USA), South Africa, and Hawaii, illustrate its global presence. The species is closely related to Hanseniaspora clermontiae, as determined by genetic sequencing, placing it within a well-defined taxonomic group. Its inability to grow at 35 °C, including normal human body temperature, suggests it is not a human pathogen, though its pathogenic potential is not fully known. The yeast's distinctive apiculate cell shape, bipolar budding, and hat-shaped ascospores are characteristic features. Its fermentation profile—fermenting glucose and cellobiose but not several other common sugars—helps distinguish it from related species. The species was named after Piet Meyer, a young South African scientist, honoring his contributions. Overall, H. meyeri contributes to understanding yeast biodiversity and ecology in natural and human-associated environments.

Did You Know?

• It has been isolated from spoiled grape punch in Georgia, USA.
• It forms two to four hat-shaped ascospores on 5% Difco malt extract agar.