Streptomyces marispadix sp. nov., isolated from marine beach sediment

Abstract

A novel actinomycetal strain, designated M600PL45_2^T, was isolated from marine sediments obtained from Ingleses beach, Porto, on the Northern Coast of Portugal and was subjected to a polyphasic taxonomic characterisation study. The here described Gram-reaction-positive strain is characterised by the production of a brown pigment in both solid and liquid medium and forms typical helical hyphae that differentiate into smooth spores. The results of a phylogenetic analysis based on the 16S rRNA gene sequence indicated that M600PL45_2^T has a high similarity to two members of the genus Streptomyces, Streptomyces bathyalis ASO4wet^T (98.51 %) and Streptomyces daqingensis NEAU ZJC8^T (98.44 %). The genome of M600PL45_2^T has a size of 6 695 159 bp, a DNA G+C content of 70.71 mol% and 5538 coding sequences. M600PL45_2^T grows at 15-37 °C and with a maximal growth rate between 25 °C and 30 °C. Growth at pH 6.0 to 9.0 with the optimal range between 6.0 and 7.5 was observed. M600PL45_2^T showed a high salinity tolerance, growing with 0-10 % (w/v) NaCl, with best growth with 1-3% (w/v) NaCl. Major cellular fatty acids are iso-C_15:0 (25.03 %), anteiso-C_15:0 (17.70) and iso-C_16:0 (26.90 %). The novel isolate was able to grow in media containing a variety of nitrogen and carbon sources. An antimicrobial activity screening indicated that an extract of M600PL45_2^T has inhibitory activity against Staphylococcus aureus. On the basis of the polyphasic data, M600PL45_2^T (= CECT 30365^T = DSM 114036^T) is introduced as the type strain of a novel species, that we named Streptomyces marispadix sp. nov.

Keywords: Actinomycetota; Streptomyces; antimicrobial activity; genome mining; novel taxa.