Leucobacter chironomi sp. nov., a chromate-resistant bacterium isolated from a chironomid egg mass.

A Gram-positive, rod-shaped, aerobic, non-motile, yellow-pigmented bacterial strain, designated MM2LB(T), was isolated from a chironomid egg mass that was sampled in a waste stabilization pond in northern Israel. 16S rRNA gene sequence analysis indicated that the isolate should be placed in the genus Leucobacter (family Microbacteriaceae). Levels of 16S rRNA gene sequence similarity between strain MM2LB(T) and the type strains of recognized Leucobacter species were 97.1 % or lower. The dominant cellular fatty acids of strain MM2LB(T) were anteiso-C(15 : 0), iso-C(16 : 0) and anteiso-C(17 : 0), which are typical of members of the genus Leucobacter. Strain MM2LB(T) grew at 17-37 degrees C, in the presence of 0-7.0 % NaCl and at pH 4.0-9.5. Cell-wall amino acids were alanine, glycine, threonine, 2,4-diaminobutyric acid, glutamic acid and gamma-aminobutyric acid in a B-type cross-linked peptidoglycan. The quinone system consisted of menaquinones MK-11, MK-10 and MK-12. The novel isolate was able to grow in medium containing 18 mM Cr(VI). On the basis of phenotypic properties and phylogenetic distinctiveness, strain MM2LB(T) is considered to represent a novel species of the genus Leucobacter, for which the name Leucobacter chironomi sp. nov. is proposed. The type strain is MM2LB(T) (=LMG 24399(T)=DSM 19883(T)).