Genome sequence analysis and bioactivity profiling of marine-derived actinobacteria, Brevibacterium luteolum, and Cellulosimicrobium funkei.

Genome analysis gives important insights into the biosynthetic potential of marine actinobacteria. The genomes of two marine actinomycetes Brevibacterium luteolum MOSEL-ME10a and Cellulosimicrobium funkei MOSEL-ME6 were sequenced to identify the biosynthetic gene clusters (BGCs). Additionally, anti-proliferative, antioxidant, and enzyme inhibitory activities were studied in vitro. We report a total genome size of 2.77 Mb with GC content of 67.8% and 6.81 Mb with GC content of 69% for Brevibacterium sp. MOSEL-ME10a and Cellulosimicrobium sp. MOSEL-ME6, respectively. Biosynthetic gene clusters (BGCs) encoding different classes of natural products were predicted including terpenes, peptides, siderophores, ectoines, and bacteriocins. The bioactivity potential of crude extracts derived from these strains was evaluated. Notable anti-proliferative activity was observed against HepG2 cell line (hepatocellular carcinoma) with an IC50 value of 182 µg/mL for Brevibacterium sp. MOSEL-ME10a. Furthermore, antioxidant activity was assessed with IC50 values of 48.91 µg/mL and 102.5 µg/mL for Brevibacterium sp. MOSEL-ME10a and Cellulosimicrobium sp. MOSEL-ME6, respectively. Protein kinase inhibition potential was observed only for Brevibacterium sp. MOSEL-ME10a. Our study also reports lower amylase enzyme inhibition potential for both strains. Moreover, both crude extracts showed only slight-to-no toxic effect on erythrocytes at 400 µg/mL and below, indicating erythrocyte membrane stability. Our data present the genomic features revealing biosynthetic potential of marine actinobacteria as well as biological activities found in vitro.