Pichia ureolytica L. C. Guo, Y. J. Shang, F. Y. Bai & P. J. Han, 2025

Pichia ureolytica L. C. Guo, Y. J. Shang, F. Y. Bai & P. J. Han sp. nov.

Etymology.

The specific epithet ureolytica (u. re. o. ly’ti. ca. L. fem. adj.) derived from “ urea ” (the compound that can be broken down) and “ lyticus, ” which indicates the ability to break down or decompose urea.

Type.

The holotype CGMCC 2.6825 (original number = 3 L- 19-1) was isolated from bark of Quercus wutaishansea collected from Mentougou district , Beijing city, China (39.866 ° N; 115.598 ° E; warm temperate semi-humid and semi-arid monsoon climate) by Y. J. Shang in August 2021 and had been deposited in a metabolically inactive state in the China General Microbiological Culture Collection Centre ( CGMCC), Beijing, China GoogleMaps . The ex-type culture had been deposited in the Japan Collection of Microorganisms (JCM), Koyadai, Japan, as JCM 36370. GenBank accessions: ITS - PQ 586091 and LSU - PQ 586297.

Culture characteristics.

After growth on YPD agar for 3 days at 25 ° C, colonies are white, circular, butyrous and smooth with entire margins (Fig. 4 A View Figure 4 ). Cells are ovoid (3.5–5.0 × 3.8–5.2 μm) and occur singly or in pairs. Budding is multilateral and pseudohyphae are not formed (Fig. 4 B View Figure 4 ). Asci (4.7–5.4 × 5.5–6.2 μm) are persistent, typically forming four spherical spores within a diamond-shaped or subrounded ascus. (Fig. 4 C View Figure 4 ). The sexual structures were observed on YCB agar after 30 days at 25 ° C.

Physiological and biochemical characteristics.

Glucose fermentation is weak. Glucose, ethanol, succinic acid (slow / weak) and DL-lactic acid are assimilated as sole carbon sources. Galactose, L-sorbose, D-xylose, D-glucosamine, glycerol, glucitol, sucrose, maltose, cellobiose, trehalose, lactose, melibiose, raffinose, melezitose, inulin, soluble starch, N-acetyl-D-glucosamine, L-arabinose, D-arabinose, xylitol, D-ribose, L-rhamnose, methanol, erythritol, ribitol, galactitol, D-mannitol, α-methyl-D-glucoside, salicin, D-glucuronic acid, sodium citrate dihydrate, inositol and hexadecane are not assimilated as sole carbon sources. Ethylamine hydrochloride, cadaverine dihydrochloride, L-lysine and ammonium sulfate are assimilated as sole nitrogen sources. Potassium nitrate and sodium nitrite are not assimilated as sole nitrogen sources. Growth in vitaminfree medium and on 50 % and 60 % (w / v) glucose are positive, while growth in 10 % NaCl plus 5 % glucose medium is negative. Urease activity is positive (Suppl. material 4). Diazonium blue B reaction and production of extracellular starchlike compounds are negative. Growth on YPD agar at 30 ° C is positive, but negative at 37 ° C.

Notes.

Pichia ureolytica is physiologically differentiated from its closely related species Pichia paraexigua and Pichia scutulata in terms of urease activity; from its closely related species Pichia bovicola and Pichia phayaonensis by growth on 60 % (w / v) glucose; from its closely related species Pichia exigua and Pichia occidentalis by the fact that Pichia exigua and Pichia occidentalis are capable of growth at 37 ° C, whereas Pichia ureolytica does not show growth under the same temperature conditions.