Volumetric Oxygen Transfer Coefficient Effect on Biomass, Bioactive Compounds Production, and Kinetic Behavior of G. lucidum in Submerged Culture Using a Complex Medium

Abstract

The effect of volumetric oxygen mass transfer coefficient (KLa) on the biomass and the commercial interest biomolecules production, was studied in the Ganoderma lucidum submerged culture using a lowcost complex medium. The batch culture was carried out in a 14 L stirred tank bioreactor, a KLa initial value set at 5.3 h-1 had a positive effect on exopolysaccharides production, achieving a maximum concentration of 1.15 g/L, under this condition, biomass production was negatively affected. An increase in the KLa initial values between 17.3 - 32.8 h-1, allowed us to obtain a culture with better oxygen and nutrients transfer conditions. These values improved the kinetic carbohydrate uptake, fungal growth, and enabled the adequate supply of oxygen for a long time, achieving a maximum biomass concentration of 9.8 g/L. Under these conditions, the average production of exopolysaccharides is 0.46 g/L, and crude protein extract production was around 0.3 g/L. The complex medium (made from barley flour) used in this study is a low-cost medium that showed great potential for the replacement of synthetic high-cost media that are conventionally used in Ganoderma lucidum submerged cultures in a stirred tank bioreactor.