Geodermatophilus poikilotrophi sp. nov. : A Multitolerant Actinomycete Isolated from Dolomitic Marble

Abstract EN

A novel Gram-reaction-positive, aerobic actinobacterium, tolerant to mitomycin C, heavy metals, metalloids, hydrogen peroxide, desiccation, and ionizing- and UV-radiation, designated G18T, was isolated from dolomitic marble collected from outcrops in Samara (Namibia).

The growth range was 15–35°C, at pH 5.5–9.5 and in presence of 1% NaCl, forming greenish-black coloured colonies on GYM Streptomyces agar.

Chemotaxonomic and molecular characteristics of the isolate matched those described for other representatives of the genus Geodermatophilus.

The peptidoglycan contained meso-diaminopimelic acid as diagnostic diaminoacid.

The main phospholipids were phosphatidylethanolamine, phosphatidylcholine, phosphatidylinositol, and small amount of diphosphatidylglycerol.

MK-9(H4) was the dominant menaquinone and galactose was detected as diagnostic sugar.

The major cellular fatty acids were branched-chain saturated acids iso-C16:0 and iso-C15:0 and the unsaturated C17:1ω8c and C16:1ω7c.

The 16S rRNA gene showed 97.4–99.1% sequence identity with the other representatives of genus Geodermatophilus.

Based on phenotypic results and 16S rRNA gene sequence analysis, strain G18T is proposed to represent a novel species, Geodermatophilus poikilotrophi.

Type strain is G18T (= DSM 44209T = CCUG 63018T).

The INSDC accession number is HF970583.

The novel R software package lethal was used to compute the lethal doses with confidence intervals resulting from tolerance experiments.