Study of the Effect of Oxygen Mass Transfer between Gas and Liquid on Production Reaction of Monascus Red Pigments by Monascus ruber

Abstract

This study was designed to culture Monascus ruber NBRC 32318 using a liquid medium composed mainly of rice starch, to obtain knowledge of pigment-forming and oxygen transfer to the liquid phase from the gas phase. When culture was performed in 500 mL Erlenmeyer flask with baffles by varying (1) the shaking speed from 40 to 200 rpm with the fixed culture volume of 100 mL and (2) the shaking culture volume from 50 to 250 mL with the fixed shaking speed of 120 rpm, the maximum value of pigment concentration were obtained in (1) 160 rpm and (2) 100 mL, respectively. Cell mass concentration and pigment concentration were evaluated by volumetric liquid-phase mass transfer coefficient (k_La) of oxygen, and it is confirmed that both parameters increased with increase of k_La but reached to plateau over 100 h^-1 of k_La.