Genome mining reveals secondary metabolites of Antarctic bacterium Streptomyces albidoflavus related to antimicrobial and antiproliferative activities

Abstract

The urgent need for new antimicrobials arises from antimicrobial resistance. Actinobacteria, especially Streptomyces genus, are responsible for production of numerous clinical antibiotics and anticancer agents. Genome mining reveals the biosynthetic gene clusters (BGCs) related to secondary metabolites and the genetic potential of a strain to produce natural products. However, this potential may not be expressed under laboratory conditions. In the present study, the Antarctic bacterium was taxonomically affiliated as Streptomyces albidoflavus ANT_B131 (CBMAI 1855). The crude extracts showed antimicrobial activity against both fungi, Gram-positive and Gram-negative bacteria and antiproliferative activity against five human tumor cell lines. Whole-genome sequencing reveals a genome size of 6.96 Mb, and the genome mining identified 24 BGCs, representing 13.3% of the genome. The use of three culture media and three extraction methods reveals the expression and recovery of 20.8% of the BGCs. The natural products identified included compounds, such as surugamide A, surugamide D, desferrioxamine B + Al, desferrioxamine E, and ectoine. This study reveals the potential of S. albidoflavus ANT_B131 as a natural product producer. Yet, the diversity of culture media and extraction methods could enhance the BGCs expression and recovery of natural products, and could be a strategy to intensify the BGC expression of natural products.