Enhanced shear protection and increased production of an anti-tumor polysaccharide by Agaricus blazei in xanthan-supplemented cultures

Abstract

Xanthan supplementation provided shear protection and stimulated polysaccharide production by Agaricus blazei. In xanthan-free cultures, the optimal cell yield, 0.63 g biomass g⁻¹ glucose, and product yield, 0.19 g polysaccharide g⁻¹ glucose, were, respectively, when the critical impeller tip speed was 50.3 cm s⁻¹ and 100.5 cm s⁻¹. Furthermore, the critical impeller tip speed of cell yield shifted from 50.3 cm s⁻¹ to 100.5 cm s⁻¹ with the supplementation of 1 g xanthan l⁻¹. Maximum specific product yield, namely 0.74 g polysaccharide g⁻¹ biomass, was achieved with inlet air supply of 3% O₂ and impeller tip speed of 100.5 cm s⁻¹.