Efficiency of Mycelial Biomass and Bioactive Compound Production by Lentinus squarrosulus Mycelia Grown in an Airlift Bioreactor as a New Source of Cosmeceutical Biological Substances

Cosmeceutical industry is continually searching for new substances or extracts from natural sources that are nontoxic and can delay the aging process. Lentinus squarrosulus is a wild edible mushroom valued by local communities in Asian countries as food as well as its medicinal benefits. However, the bioactive substances and cosmeceutical biological properties of L. squarrosulus mycelia grown in submerged culture have not been demonstrated. This study aims to investigate the feasibility of producing L. squarrosulus mycelial biomass and cosmeceutical bioactive compounds through large-scale submerged fermentation. L. squarrosulus mushroom mycelia grown in a 5-L airlift bioreactor submerged culture was investigated as a new source of cosmeceutical biological substances. An ethanolic extract derived from L. squarrosulus mycelia possesses potential antioxidant agents capable of inhibiting dermal enzymes such as collagenase, elastase, and tyrosinase for simultaneously treating skin aging and hyperpigmentation. The Molisch test, FTIR analysis, and b-glucan assays revealed that the main polysaccharide present in the L. squarrosulus mycelial extract was b-glucan (64.3 %), which acts as a major contributor to its cosmeceutical properties. The L. squarrosulus mycelial extract was non-toxic to human skin keratinocytes (HaCaT). Cosmeceutical formulations developed with the mycelial extract, especially in essence form, preserved the extract’s bioactivities, presented a pale-yellow color and a pH of 6.0, which is considered suitable for cosmeceutical design. This study provides new information regarding submerged growth of L. squarrosulus mycelia in an airlift bioreactor, which has potential as a novel source of useful bioactive b-glucans for cosmeceutical applications. High mycelial biomass was produced over a short time in this airlift bioreactor that concomitantly had anti-aging and skin whitening properties. The results suggest that the mycelial extracts of L. squarrosulus could be further developed to produce safe natural ingredients for inclusion in cosmeceutical products. HIGHLIGHTS This is the first report detailing the submerged growth of Lentinus squarrosulus mushroom mycelia in an airlift bioreactor. L. squarrosulus mycelia grown submerged in an airlift bioreactor is a new source of b-glucan with multifunctional cosmeceutical properties. Ethanolic extracts of L. squarrosulus mycelia have the potential to simultaneously treat skin aging and hyperpigmentation. GRAPHICAL ABSTRACT