Application of different feeding strategies in fed batch culture for pullulanase production using sago starch

•Application of congo red dye on pullulan agar to detect pullulanase activity.•Utilization of sago starch for pullulanase production.•Comparison of pullulanase production in batch and fed batch culture.•Application of fix mode and variable mode fed batch system.•Maltose, maltotriose and panose production in batch and fed batch culture. The production of pullulanase by Bacillus flavothermus KWF-1 in batch and fed batch culture were compared using 2L bioreactor. In batch culture, 0.0803U/mL of pullulanase activity with specific activity of 0.0213U/mg was produced by controlling the agitation speed and temperature at 200rpm and 50°C, respectively. Fed batch production was studied by feeding the culture with different sago starch concentrations in various feeding modes for enhanced pullulanase production. Exponential feeding mode at dilution rate of 0.01/h was the preeminent strategy for enhanced pullulanase production of 0.1710U/mL with specific activity of 0.066U/mg. It had shown an increment of pullulanase production and specific activity by 2.1 and 3.1-fold, respectively when compared to batch culture. Increment of pullulanase activity in exponential feeding mode improved hydrolyzation of sago starch into maltotriose and panose by 4.5 and 2.5-fold respectively compared to batch system.