Olivibacter sitiensis gen. nov., sp. nov., isolated from alkaline olive-oil mill wastes in the region of Sitia, Crete

Abstract

A novel, Gram-negative, non-motile, non-sporulating, rod-shaped bacterium isolated from a viscous two-phase olive-oil mill waste (‘alpeorujo’) is described. The strain, designated AW-6T, is an obligate aerobe, forming irregular, pigmented creamy white colonies. The pH and temperature ranges for growth were pH 5–8 and 5–45 °C, with optimal pH and temperature for growth of pH 6–7 and 28–32 °C, respectively. Strain AW-6T was chemo-organotrophic and utilized mostly d(+)-glucose, protocatechuate and d(+)-xylose, followed by l-cysteine, d(−)-fructose, d(+)-galactose, l-histidine, lactose, sorbitol and sucrose. Menaquinone-7 was detected in the respiratory chain of strain AW-6T. The major fatty acids of strain AW-6T were C16 : 1 ω7c and/or iso-C15 : 0 2-OH, iso-C15 : 0, iso-C17 : 0 3-OH and C16 : 0. The closest phylogenetic relative of strain AW-6T was clone BIti35 (89.7 % 16S rRNA gene sequence similarity), while Sphingobacterium thalpophilum DSM 11723T was the closest recognized relative within the Sphingobacteriaceae (88.2 % similarity). Strain AW-6T showed a low level of DNA–DNA relatedness to S. thalpophilum DSM 11723T (33.8–37.0 %). The DNA G+C content of strain AW-6T was 45.6 mol%. Physiological and chemotaxonomic data further confirmed the distinctiveness of strain AW-6T from members of the genera Sphingobacterium and Pedobacter. Thus, strain AW-6T is considered to represent a novel species of a new genus within the family Sphingobacteriaceae, for which the name Olivibacter sitiensis gen. nov., sp. nov. is proposed. The type strain is AW-6T (=DSM 17696T=CECT 7133T).