Highly efficient production of transfructosylating enzymes using low-cost sugarcane molasses by A. pullulans FRR 5284

Abstract

Fructooligosaccharides (FOS) are a type of important prebiotics and produced by transfructosylating enzymes. In this study, sugarcane molasses was used as the substrate for production of transfructosylating enzymes by Aureobasidium pullulans FRR 5284. NaNO3 was a superior nitrogen source to yeast extract for production of transfructosylating enzymes by A. pullulans FRR 5284 and decreasing the ratio of NaNO3 to yeast extract nitrogen from 1:0 to 1:1 resulted in the reduction of the total transfructosylating activity from 109.8 U/mL to 82.5 U/mL. The addition of only 4.4 g/L NaNO3 into molasses-based medium containing 100 g/L mono- and di-saccharides resulted in total transfructosylating activity of 123.8 U/mL. Scale-up of the A. pullulans FRR 5284 transfructosylating enzyme production process from shake flasks to 1 L bioreactors improved the enzyme activity and productivity to 171.7 U/mL and 3.58 U/mL/h, 39% and 108% higher than those achieved from shake flasks, respectively. Sucrose (500 g/L) was used as a substrate for extracellular, intracellular, and total A. pullulans FRR 5284 transfructosylating enzymes, with a maximum yield of 61%. Intracellular, extracellular, and total A. pullulans FRR 5284 transfructosylating enzymes from different production systems resulted in different FOS profiles, indicating that FOS profiles can be controlled by adjusting intracellular and extracellular enzyme ratios and, hence prebiotic activity. [Figure not available: see fulltext.]