Toward the formulation of bio-cosmetic nanoemulsions: from plant-derived to microbial-derived ingredients

Consumers of face-care cosmetics have been continuously evolving and are more receptive to skin-care products that integrate both health and wellness. This subsequently prompted cosmetic manufacturers to renew their formulation approaches by allowing gradual replacement of synthetic ingredients with promising natural alternatives. Among various available forms of skin-care cosmetic agents, the nanoemulsion system is generally regarded as an efficient carrier for the sustained delivery of bioactive ingredients. In this review, various aspects of nanoemulsion systems used in cosmetic applications such as their formulation methods, destabilizing mechanisms, testing methods have been briefly discussed. The gradual transition in present-day cosmetics toward sustainable green-cosmetics has been appropriately captured and deliberated by quoting relevant examples of some existing ingredients, which are derived from plant, animal and microbial sources. Furthermore, the scientific advancements in search of a promising bio-emulsifier have been delineated through discussion on emerging microbial surfactants candidates, with a special focus on surfactin- a lipopeptide obtained from Bacillus Subtilis. Finally, a holistic approach for the formulation of microbial cosmetics, i.e., a cosmetic formulation with full microbial-derived ingredients, has been proposed.