The skin microbiome is composed of a complex association of bacteria, fungi, and viruses. The maintenance of skin commensal microbes is essential for preventing the overgrowth of pathogenic microorganisms or already present opportunistic pathogens. Thus, the development of bioactive compounds capable of modulating skin microbiome has become an important topic for both researchers and the cosmetic industry. Increasingly, scientific evidence highlights that metabolites derived from probiotics have a great potential to prevent diseases affecting the skin. These compounds have recently been called postbiotics and are defined as a “preparation of inanimate microorganisms and/or their components that confers a health benefit on the host”. Postbiotics are obtained from fermentations performed almost exclusively by lactic acid bacteria and yeast. Short-chain fatty acids, bacteriocins, and organic acids are some examples of postbiotics. These compounds exhibit antimicrobial, immunomodulatory, antioxidant, and anti-inflammatory activities. In addition, postbiotic production possesses technological advantages, including high stability and increased safety, compared to viable probiotics. In this article, a model for the large-scale production of postbiotics and their uses in cosmetic formulations are reviewed. In addition, results obtained from in vivo tests for the treatment of alopecia, acne, atopic dermatitis, and wound healing are discussed. Finally, technological advances are shown based on a survey of the main patents filed in the area of postbiotics.

Application of date palm waste compost is quite beneficial in improving soil properties and crop growth. However, the effect of its application on soil microbial communities is less understood. High-throughput sequencing and quantitative real-time PCR (qPCR) were used to evaluate the effect of compost application on the soil microbial composition in a barley field during the tillering, booting and ripening stages. The results showed that compost treatment had the highest bacterial and fungal abundance, and its application significantly altered the richness (Chao1 index) and α-diversity (Shannon index) of fungal and bacterial communities. The dominant bacterial phyla found in the samples were Proteobacteria and Actinobacteria while the dominant fungal orders were Ascomycota and Mortierellomycota. Interestingly, compost enriched the relative abundance of beneficial microorganisms such as Chaetomium, Actinobacteriota, Talaromyces and Mortierella and reduced those of harmful microorganisms such as Alternaria, Aspergillus and Neocosmospora. Functional prediction based on Phylogenetic Investigation of Communities by Reconstruction of Unobserved States (PICRUSt) showed that amplicon sequence variant (ASV) sequences related to energy metabolism, amino acid metabolism and carbohydrate metabolism were associated with compost-treated soil. Based on Fungi Functional Guild (FUNGuild), identified fungi community metabolic functions such as wood saprotroph, pathotroph, symbiotroph and endophyte were associated with compost-treated soil. Overall, compost addition could be considered as a sustainable practice for establishing a healthy soil microbiome and subsequently improving the soil quality and barley crop production.