Phylogenetic Diversity and Enzymatic Activities of Cultivable Actinomycetes Isolated from Marine Sediment at Ain Achir (Gulf of Annaba, Algeria)

Abstract

Abstract Algerian marine sediments are an underexplored and potentially rich source of microorganisms that may produce useful metabolites and enzymes. Here, we investigated the phylogenetic diversity and enzymatic activities of suspected Actinomycetia bacteria isolated from seabed sediment at Ain Achir, Gulf of Annaba, Algeria. Morphological, physiological and taxonomical properties were characterized and their potential to produce enzyme activities was studied. Phylogenetic analysis of partial 16S rRNA gene sequences assigned isolates into five main genera: Rhodococcus (21/35), Microbacterium (5/35), Streptomyces (3/35), Brevibacterium (2/35) and Agromyces (2/35). Screening for 14 enzymatic activities demonstrated their abilities to metabolize a wide range of substrates including DNA, L-asparagine, and L-glutamine (each degraded by all 35 isolates). Other substrates degraded by most isolates included uric acid and urea (both 33/35), starch (25/35) and tyrosine (24/35). Moreover, the number of enzymatic activities possessed by the isolates ranged from six (one isolate) to 10 (four isolates). This study is the first to investigate the phylogenetic diversity and enzymatic activities of actinomycetes isolated from sea sediment in the Gulf of Annaba and it confirms that actinomycetes from the marine environment are a valuable source of enzymes, with further investigation required to unlock their potential commercial applications.