Oceanobacillus chironomi sp. nov., a halotolerant and facultatively alkaliphilic species isolated from a chironomid egg mass.

Chironomids (Diptera; Chironomidae) are the most abundant insects in freshwater aquatic habitats. Females of the genus Chironomus lay egg masses containing hundreds of eggs embedded in a gelatinous matrix. A bacterial strain, designated T3944D(T), was isolated from a chironomid egg mass sampled from a waste-stabilization pond in northern Israel and was found to be Gram-positive, motile by peritrichous flagella, endospore-forming, halotolerant and facultatively alkaliphilic. Comparative 16S rRNA gene sequence analysis showed that strain T3944D(T) belonged to the genus Oceanobacillus, exhibiting the highest levels of similarity with the sequences of Oceanobacillus oncorhynchi subsp. incaldanensis DSM 16557(T) (94.9 %), Oceanobacillus oncorhynchi subsp. oncorhynchi JCM 12661(T) (94.8 %), Oceanobacillus iheyensis JCM 11309(T) (94.7 %) and Oceanobacillus picturae LMG 19416 (94.5 %). Strain T3944D(T) grew optimally at 1-3 % NaCl, pH 8.5 and 37 degrees C. The major cellular fatty acids were anteiso-C(15 : 0) (60.0 %) and anteiso-C(17 : 0) (12.9 %) and the DNA G+C content was 38.1 mol%. On the basis of its phenotypic properties and phylogenetic distinctiveness, strain T3944D(T) represents a novel species in the genus Oceanobacillus, for which the name Oceanobacillus chironomi sp. nov. is proposed. The type strain is T3944D(T) (=LMG 23627(T)=DSM 18262(T)).