An iterative approach to statistical optimization of exopolysaccharide produced by fermentation of Aureobasidium pullulans

Exopolysaccharides are biopolymers with wide-ranging industrial applications. To substitute fossil-based by bio-based, biodegradable polymers, exopolysaccharide production needs to become much more efficient. Pullulan, produced by Aureobasidium pullulans, is popular for its unique properties like film-formation, adhesiveness, biodegradability, etc. This study aims at demonstrating the optimization strategy on pullulan production using statistical optimization iteratively. The process followed a systematic approach including One Factor at A Time (OFAT) and Design Of Experiments (DOE). OFAT confirmed sucrose as carbon source, pH 6 and 4 days of incubation were optimum. Iterative Plackett-Burman Design (PBD) and Response Surface Methodology (RSM) further demonstrated interactions between significant media components and incubation conditions. The final pullulan titer was increased 6.34-fold to 113.5 ± 3.5 g/L of EPS, the highest titer achieved for this strain in shake flasks. Future investigations into fed-batch strategies and scale-up studies can be explored to further improve titers and reduce overall production costs.