Detecting and Analyzing Hydrolytic Enzymes of Industrial Significance in two Streptomyces Strains Isolated from the Soil

Two Streptomyces strain were isolated from a soil sample in Louisiana. They were identified via 16S rRNA sequencing and phylogeny. To detect the presence of hydrolytic enzymes, starch, carboxymethyl-cellulose (CMC), lipase reagent, and Milk (casein) were used as substrate to detect the production of amylase, cellulose, lipase and casease respectively. Both strains showed the ability to hydrolyze starch, and cellulose, while only strain SWHR10 displayed lipase activity. In addition, strain SWHR10 showed better amylase and cellulase activity. Hemolysis, gelatinase and catalase tests were also conducted. This study further validates that Streptomyces remain a powerhouse of hydrolytic enzymes with industrial and economic importance.

Draft Genome Sequence of Streptomyces Strain SJ1-7, a Soil Bacterial Isolate

ABSTRACT The draft genome sequence of Streptomyces strain SJ1-7, a bacterial strain isolated from the rhizosphere of a Pinus densiflora plant, is reported. The whole-genome assembly comprised 7.9 Mbp, with a GC content of 71.80% and 4,262 predicted protein-coding genes.

Effective approaches to discover new microbial metabolites in a large strain library

Natural products have provided many molecules to treat and prevent illnesses in humans, animals and plants. While only a small fraction of the existing microbial diversity has been explored for bioactive metabolites, tens of thousands of molecules have been reported in the literature over the past 80 years. Thus, the main challenge in microbial metabolite screening is to avoid the re-discovery of known metabolites in a cost-effective manner. In this perspective, we report and discuss different approaches used in our laboratory over the past few years, ranging from bioactivity-based screening to looking for metabolic rarity in different datasets to deeply investigating a single Streptomyces strain. Our results show that it is possible to find novel chemistry through a limited screening effort, provided that appropriate selection criteria are in place.

Isolation and Characterization of a New Streptomyces strain LG10 from an Unexploited Algerian Saharan Atlas

An actinobacterial strain named LG10 was isolated from a Saharan Atlas soil (Laghouat, Algeria). The aerial hyphae were yellowish-white on all culture media with rectiflexibiles spore chains, suggested that this bacterium attached to Streptomyces. Furthermore, LG10 contained chemical characteristics that were diagnostic for the genus Streptomyces, such as the presence of LL-diaminopimelic acid isomer (LL-DAP) and glycine amino acid. The hydrolysates of whole-cell included non-characteristic sugars. Comparative analysis of the 16S rDNA sequence displayed a similarity level of 100% with Streptomyces puniceus NRRL ISP-5058T. The antimicrobial activity of the LG10 strain was better in the culture medium MB5. Streptomyces strains are good sources of bioactive compounds with multiple biological activities.

Critical review of fermentation and extraction of anti-Vibrio compounds from Streptomyces

A single Streptomyces strain often have the potential to produce more than one bioactive compound. Fermentation parameters include media compositions, temperature and pH, have great impact on the secondary metabolism of Streptomyces and subsequently on production of different microbial products. This review aims to consolidate the studies on the cultivation parameters used to enhance the production of secondary metabolite with anti-Vibrio activity from a single Streptomyces strain. In turn, this review sheds light on the possible alterations of the cultivation parameters to obtain desired anti-Vibrio compounds from Streptomyces sp. Furthermore, the bioactive compounds with anti-Vibrio activity identified from Streptomyces sp. were demonstrated to exhibit immense values for future antibacterial agent developments.