Enhancement of phenolics extraction from red algae (Kappaphycus spp.) using solid-state fermentation

The effects of solid-state fermentation (SSF) on microbial growth contribute to the bioenrichment and availability of phenolic compounds in different varieties of Kappaphycus spp. red algae through the action of hydrolytic enzymes produced are investigated. Three different red algae samples were used; K. striatum var. green flower (GF), K. alvarezii var. white giant (WG) and K. alvarezii var. purple giant (PG). SSF was performed using A. oryzae for 0 to 6 days at 30°C. Results obtained demonstrated that the highest (p<0.05) extraction of phenolics (10.022 mg GAE/g and 14.90 mg CE/g), and antioxidant properties (72.47% activity of DPPH radical scavenging and 18.23 mM/g FRAP value respectively) was obtained for GF sample at day 4 of fermentation. Cellulase, βglucosidase, and xylanase were found to be responsible for enhancing phenolics and antioxidant activity of WG and GF varieties by releasing bound phenolics. However, for the PG sample, β-glucosidase showed a significant relationship with TPC and antioxidant activity.