Insights into the extraction, characterization and antifungal activity of astaxanthin derived from yeast de-oiled biomass

Abstract

The increasing popularity of bio-based oil in fuel, cosmetics and pharmaceutical industry has led the path of innovations where microbes are exploited as an alternative source. Thus, complete valorizationof left-over microbial biomass generated during these industrial fermentations will also address the environmental concern of its disposal. In line, current investigation utilizes residual de-oiled (lipid extracted) biomass of red oleaginous yeast, Rhodosporidium paludigenum for astaxanthin (AST) production and compares various cell disruption methods; conventional extraction, ultrasonic homogenization, cryogenic treatment for its efficient recovery. Among all, cryogenic treatment was found most promising and resulted in the highest AST yield ( ∼ 7.1 ± 0.72 mg/g wet cell weight) with improved extraction efficiency (47.94 %). The sub-zero temperature during this method facilitated complete homogenization of cells as well as helped to maintain the structural and functional integrity of recovered AST. Furthermore, the mechanistic insights in the antifungal action of extracted AST was also elucidated in C. albicans and C. glabrata . The data suggested that AST mediated reductive stress in biofilm cells interfered with intracellular signalling and resulted in membrane porosity, mitochondrial dysfunction leading eventual cell apoptosis. Conclusively, outcomes of this study propose a sustainable approach for AST extraction from de-oiled yeast biomass with detailed insight into its therapeutic activity. • Yeast de-oiled biomass used to produce astaxanthin (AST). • Cryogenic treatment and conventional methods are discussed for cell lysis. • Recovered AST showed comparable antioxidant activity with standard form. • Future directions on development of AST as antibiofilm agent are proposed.