Effects of Tween series and agar additives on mycelia biomass and β-glucan production by Hericium erinaceus in submerged culture

Hericium erinaceus has been widely used in food and medicine because of its various promising bioactivities. This study investigated the effects of Tween series surfactant and agar addition on mycelial growth and β-glucan in liquid submerged culture of the medicinal mushroom H. erinaceus. The addition of Tween 80 in liquid medium resulted in higher dry cell weight (DCW) and β-glucan production, with values of 6.06 and 1.21 g/L for 3.0% (w/v) and 7.27 and 1.22 g/L for 4.0% (w/v), respectively. This corresponded to a 1.82 relative ratio of DCW to control and a 1.86 relative ratio of β-glucan to control for 3.0% (w/v) and a 2.18 relative ratio of DCW to control and a 1.87 relative ratio of β-glucan to control for 4.0% (w/v), respectively. Further, the mycelial pellets were altered by the addition of agar in liquid medium, forming small pellets. The pellet diameter decreased with increasing medium viscosity, and the smallest pellet diameter, 1.5 mm, was attained with the addition of 0.3% (w/v) agar. The medium viscosity was 48.7 mPa s. Moreover, β-glucan production increased with a decreasing pellet diameter, and the highest β-glucan production, 0.86 g/L, was observed with 0.3% (w/v) agar added to the medium. The influence of flask type on DCW and β-glucan production was investigated which were almost 1.2-fold higher in baffled Erlenmeyer flasks than in normal Erlenmeyer flasks. Finally, cultivation with agar addition in a baffled Erlenmeyer flask was determined to be most effective for DCW and β-glucan production, yielding the highest values of 7.74 and 1.43 g/L, respectively.