Skincare Potential of a Sustainable Postbiotic Extract Produced Through Sugarcane Straw Fermentation by Saccharomyces Cerevisiae

Abstract

Postbiotics, a new class of molecules derived from microorganism’s metabolism, are defined as a “preparation of inanimate microorganisms and/or their components that confers a health benefit on the host”. They can be produced by fermentation, using culture media with glucose as the carbon source, and lactic acid bacteria of the genus Lactobacillus, and/or yeast, mainly Saccharomyces cerevisiae as fermentative microorganisms. Postbiotics comprise different metabolites, and have important biological properties (antioxidant, anti-inflammatory, etc), which is why their use in cosmetics should be considered. During this work, the production of postbiotics was carried out by fermentation with sugarcane straw, as a source of carbon and other active compounds, and as a more sustainable and promising process to obtain more bioactive extracts at the end. For this, its saccharification process was carried out with cellulase at 55 ºC for 24 h. Fermentation was performed sequentially after saccharification at 30 ºC, for 72h, using S. cerevisiae. The cells-free extract was characterized regarding its composition, antioxidant activity, and skincare potential. Its use was safe at concentrations below ~ 20 mg.mL− 1 for keratinocytes and ~ 7.5 mg.mL− 1 for fibroblasts. It showed antioxidant activity, with ABTS IC50 of 1.88 mg.mL− 1, and inhibited elastase and tyrosinase activities by 83.4% and 42.4%, respectively, at the maximum concentration tested (20 mg.mL− 1). In addition, it promoted the production of cytokeratin 14, and demonstrated anti-inflammatory activity at a concentration of 10 mg.mL− 1. Finally, in the skin microbiota of human volunteers, the extract inhibited the Cutibacterium acnes bacterium and the Malassezia fungal genus. In short, postbiotics were successfully produced using straw as substrate, and as source of carbon and phenolic compounds. These postbiotics showed bioactive properties that potentiate their use in the development of cosmetic and skincare products, such as the treatment of acne or other skin diseases, due to their anti-inflammatory and inhibitory effect on the bacteria responsible for acne, as well as on potentially colonizing fungi.