Microbacterium memoriense sp. nov., a member of the Actinomycetota from marine beach sediment of the north coast of Portugal


Dos Santos J.D.N., Klimek D., Calusinska M., Lobo-Da-cunha A., Catita J., Gonçalves H., González I., Lage O.M.


International Journal of Systematic and Evolutionary Microbiology, vol. 74, n° 1, art. no. 006230, 2024


The oceans harbour a myriad of unknown micro-organisms that remain unstudied because of a failure to establish the right growth conditions under laboratory conditions. To overcome this limitation, an isolation effort inspired by the iChip was per-formed using marine sediments from Memória beach, Portugal. A novel strain, PMIC_1C1BT, was obtained and subjected to a polyphasic study. Cells of strain PMIC_1C1BT were Gram-positive, rod-shaped, divided by binary fission and formed colo-nies that were shiny light-yellow. Based on its full 16S rRNA gene sequence, strain PMIC_1C1BT was phylogenetically associated to the genus Microbacterium and its closest relatives were Microbacterium aurum KACC 15219T (98.55%), Microbacterium diaminobutyricum RZ63T (98.48%) and Microbacterium hatanonis JCM 14558T (98.13%). Strain PMIC_1C1BT had a genome size of 2761607 bp with 67.71mol% of G+C content and 2582 coding sequences, which is lower than the genus average. Strain PMIC_1C1BT grew from 15 to 30°C, optimally at 25°C, at pH 6.0 to 11.0, optimally between pH 6.0 and 8.0, and from 0 to 5% (w/v) NaCl, optimally between 2.0 and 3.0%. It grew with casamino acids, glutamine, methionine, N-acetylglucosamine, sodium nitrate, tryptophan, urea and valine as sole nitrogen sources, and arabinose and cellobiose as sole carbon sources. The major cellular fatty acids were anteiso-C15:0, iso-C16:0 and iso-C17:0. Genome mining revealed the presence of four biosynthetic gene clusters (BGCs) with low similarities to other known BCGs. Based on the polyphasic data, strain PMIC_1C1BT is proposed to represent a novel species, for which the name Microbacterium memoriense sp. nov. (=CECT 30366T=LMG 32350T) is proposed.



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