Exploring microbial diversity from extreme environments, combined with targeted strategies, is a promising approach to uncover novel antimicrobial agents. In order to discover compounds with antimicrobial activity, the sulfur-containing antibiotic thiolutin was isolated and identified from strain HMX112 T using a targeted antibacterial screening strategy. Strain HMX112 T was isolated from a soil sample collected from the Turpan-Hami Basin in China and was characterized as an actinobacterium. 16S rRNA gene sequence analysis revealed that strain HMX112 T showed the highest similarity to Streptomyces lateritius CGMCC 4.1427 T , Streptomyces narbonensis CGMCC 4.1737 T , and Streptomyces purpureus DSM 43362 T , with sequence similarities of 98.83, 98.83, and 98.76%, respectively. Whole-genome analysis indicated that the average nucleotide identity (ANI) and digital DNA–DNA hybridization (dDDH) values between strain HMX112 T and its closest related type strains were well below the thresholds for novel species delineation (95 and 70%, respectively). Based on polyphasic taxonomic analysis, strain HMX112 T was confirmed to represent a novel species of the genus Streptomyces , for which the name Streptomyces flavimicrosus sp. nov. was proposed. Based on its observed antibacterial activity against Gram-positive bacteria, the bioactive components of strain HMX112 T were investigated, resulting in the isolation and identification of the secondary metabolite thiolutin. Antimicrobial assays demonstrated that thiolutin possesses broad-spectrum inhibitory activity, showing MIC values of 16 μg/mL against two MRSA strains and inhibition rates exceeding 70% against nine plant pathogenic fungi at a concentration of 50 μg/mL. Furthermore, the biosynthetic pathway of thiolutin was elucidated through genomic analysis.
Niu et al. (Fri,) studied this question.