Effect of olive oil on the production of mycelial biomass and polysaccharides of Grifola frondosa under high oxygen concentration aeration

In this research, the factors of oxygen concentration (21%, 30%, and 40%) and olive oil addition were studied on the production of mycelial biomass and polysaccharides of Grifola frondosa in a 5-L jar fermentor. The 40% oxygen was found to inhibit both cell growth and polysaccharide production with a higher rate of glucose consumption. The highest cell concentration was found at 9.29 g/L at day 9 with 1 vvm at 21% O2. With 30% O2 the inter-cellular polysaccharide (IPS) level increased earlier than 21% O2 and reached the maximum concentration at day 8 with 21.9 mg/g. On the other hand, 21% O2 reached the maximum concentration at day 11 with 19.5 mg/g. With 1% olive oil addition in 21% O2 and 40% O2, the production of mycelial biomass was enhanced and increased to 10.1 and 14.9 g/L, respectively, after 9 days’ cultivation. And the extra-cellular polysaccharide (EPS) production increased from 0.7–0.9 g/L to 2.24 g/L and 3.00 g/L at day 13 with 21% O2 and 40% O2 aeration, respectively. In addition, the IPS increased rapidly and reached the maximum level of 28.2 mg/g at day 7 and this level remained till day 13 through the whole fermentation.