There is a real consensus that new antibiotics are urgently needed and are the best chance for combating antibiotic resistance. The phylum Actinobacteria is one of the main producers of new antibiotics, with a recent paradigm shift whereby rare actinomycetes have been increasingly targeted as a source of new secondary metabolites for the discovery of new antibiotics. However, this review shows that the genus Streptomyces is still the largest current producer of new and innovative secondary metabolites. Between January 2015 and December 2020, a significantly high number of novel Streptomyces spp. have been isolated from different environments, including extreme environments, symbionts, terrestrial soils, sediments and also from marine environments, mainly from marine invertebrates and marine sediments. This review highlights 135 new species of Streptomyces during this 6-year period with 108 new species of Streptomyces from the terrestrial environment and 27 new species from marine sources. A brief summary of the different pre-treatment methods used for the successful isolation of some of the new species of Streptomyces is also discussed, as well as the biological activities of the isolated secondary metabolites. A total of 279 new secondary metabolites have been recorded from 121 species of Streptomyces which exhibit diverse biological activity. The greatest number of new secondary metabolites originated from the terrestrial-sourced Streptomyces spp.

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A gel electrolyte outperforms liquid electrolytes in conveying Li+ across the pellet–cathode interface by eliminating solvent–ion clusters and immobilizing anions.

Biofilms are association of microorganisms that attach to each other to a surface enclosed in a self-generated extracellular matrix. Virtually (99.9%) all microorganisms have the competence to form biofilm. The formation of biofilm is a complex process, in which bacterial cells transform from planktonic cells to sessile mode of growth. The biofilm development results from the expression of specific genes. Biofilms have been developed as an adaptive strategy of bacterial species to survive in adverse environmental conditions as well as to establish antagonistic or beneficial interactions with their host. Molecular interaction and details of biofilm formation are not well-understood as bacteria in the biofilm have several orders of magnitude, more resistant to antibiotics compared to planktonic bacteria. Thus, the currently available drugs typically failed to target bacterial biofilms. Quorum sensing (QS) is a process of intercellular signalling or cell-cell communication and a vital regulatory mechanism for coordinating biofilm formation including common activities and physiological processes such as symbiosis, formation of spores or fruiting bodies, antibiotics synthesis, genetic competence, apoptosis and virulence in many bacterial species using extracellular QS signalling molecules, which is often referred to as autoinducers (AIs). Microorganisms produce a wide variety of QS signalling molecules that can be self-recognized in a concentration-dependent manner and subsequently induce