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

HIGHLIGHTS

• G. lucidum is able to grow in a low-cost complex medium in a stirred tank bioreactor.

• KLa values between 17.3 - 32.8 h^-1 are suitable to scale up bioprocess using complex media.

• Oxygen availability in the bioreactor affects the biomass and biomolecules production.

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 low-cost 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.

Keywords:
bioreactor; Ganoderma lucidum; volumetric oxygen mass transfer coefficient (KLa); biomolecules; complex medium