Marine rhodophyte Porphyridium cruentum is a known source of polysaccharides, proteins, and bioactive compounds. Microalgae biomass fermentation with yeast, such as Kluyveromyces marxianus, can enhance nutritional and health properties, like protein content and antioxidant activity. Adding fermented P. cruentum biomass to fish diets could improve feed efficiency, boost immunity, and reduce mortality rates, promoting sustainable fish farming. In livestock, antioxidant ingredients help protect against oxidative stress. For human nutrition, fermented P. cruentum biomass could act as a functional component that provides a rich source of plant-based protein and antioxidants.
A three-factorial experimental design was used to investigate the effects of incubation time (24h, 48h, and 72h), glucose (0%, 1%, and 2% w/v), and K. marxianus inoculum concentration (0%, 1%, and 2% v/v) on the fermentation of 4% (w/v) aqueous solution of lyophilized P. cruentum biomass. The fermentation was conducted in Erlenmeyer flasks with a 40 mL working volume, incubated at 30°C, with orbital agitation (150 rpm) and anaerobic conditions. This study investigated the fermentation effect on protein content and antioxidant activity in P. cruentum biomass to elucidate its potential as a nutrient ingredient for aquaculture, animal feed, and human food industry.
The highest protein content (50.99±0.99 %) was observed with 48h of incubation, 1% (w/v) glucose, and 6% (v/v) K marxianus inoculum (Figure 1; P = 0.002). All treated samples showed visually higher protein content compared to untreated biomass. Antioxidant capacity also increased, positioning fermented P. cruentum as a versatile, eco-friendly ingredient that meets the nutritional demands of various industries.