Scale-Up of Pigment Production by the Marine-Derived Filamentous Fungus, Talaromyces albobiverticillius 30548, from Shake Flask to Stirred Bioreactor

Abstract

Talaromyces albobiverticillius 30548, a marine-derived fungus, produces Monascus-like azaphilone red/orange pigments which have the potential for various industrial applications. The objective of this study was to scale up pigment production in a 2 L bioreactor with a working volume of 1.3 L media and to compare its biomass growth and pigment production against small volume (500 mL) shake flasks with 200 mL working volume. Additionally, fungal morphology, pigment intensity, fermentation length and duration of pigment production were also compared. Experiments were carried out at laboratory scale in 200 mL shake flasks without controlling pH and oxygen. In parallel, fermentation was performed in a 2 L bioreactor as an initial scale-up to investigate the influence of dissolved oxygen, agitation speed and controlled pH on pigment production and biomass growth of T. albobiverticillius 30548. The highest orange and red pigment production in bioreactor at 24 °C was noticed after 160 h of fermentation (70% pO2) with 25.95 AU 470 nm for orange pigments and 22.79 AU 500 nm for red pigments, at pH set point 5.0. Meanwhile, the fermentation using 200 mL shake flasks effectively produced orange pigments with 22.39 AU 470 nm and red pigments with 14.84 AU 500 nm at 192 h under the same experimental conditions (24 °C, pH 5.0, 150 rpm). Regarding fungal morphology, growth of fungus in the bioreactor was in the form of pellets, whereas in the shake flasks it grew in the form of filaments. From the observed differences in shake flasks and closed bioreactor, it is known that the bioprocess was significantly influenced by dissolved oxygen saturation and agitation speed in scale-up. Thus, oxygen transfer appears to be the rate-limiting factor, which highly influences overall growth and production of pigments in Talaromyces albobiverticillius 30548 liquid culture.