Brevibacterium litoralis sp. nov., a cellulose-degrading strain isolated from marine surface sediment

Abstract

A Gram stain-positive, non-spore-forming, non-motile, short-rod actinomyces strain GXQ1321^T was isolated from maritime surface sediments in Beihai (21° 41′ 21.65″ N, 109° 05′ 76.56″ E), Guangxi Zhuang Autonomous Region, and a number of categorization studies were performed. Following a period of 72 h of incubation at a temperature of 30 °C within a modified actinomycete culture medium, the colony was light-yellow, circular, smooth, central bulge, convex, opaque, with a 1.2–2.3 mm diameter. Strain GXQ1321^T had the ability to degrade cellulose. Chemotaxonomic studies revealed that the major methylnaphthoquinones in strain GXQ1321^T was MK-8(H₂). The most prevalent cellular fatty acids were anteiso-C_19:0, anteiso-C_15:0, anteiso-C_17:0, and iso-C_16:0. The whole-cell sugars of the strain GXQ1321^T were identified rhamnose, xylose and glucose. Meso-diaminopimelic acid was found in the peptidoglycan hydrolysate, and the polar lipids were identified as diphosphatidylglycerol, three phosphoglycolipid, phosphatidylglycerol and two unknown glycolipid. This strain had 69.6% DNA G+C content. Strain GXQ1321^T is classified as Brevibacterium based on its 16S rRNA gene sequence. It is closely related to Brevibacterium samyangense SST-8 ^T (96.8%) and Brevibacterium rongguiense 5221 ^T (96.3%). The average nucleotide identity (ANI) values of GXQ1321^T and the above two type strains were 73.9–77.1%, and the digital DNA-DNA hybridisation (dDDH) values were 15.3–21.1%. Based on the phylogenetic, chemotaxonomic and physiological data, strain GXQ1321^T was considered to be a novel species of the genus Brevibacterium, named Brevibacterium litoralis sp. nov, with the type strain GXQ1321^T (= MCCC 1K08964^T = KCTC 59167 ^T).