Efficient production of fructo-oligosaccharides from sucrose and molasses by a novel Aureobasidium pullulan strain

The use of whole-cell biocatalyst for production of fructo-oligosaccharide (FOS) eliminates the need for costly enzyme recovery and purification. In this study, a novel Aureobasidium pullulans strain (FRR 5284) was identified from seven A. pulllulans strains as an efficient whole-cell biocatalyst for FOS production. The strain had a specific intracellular transfructosylating activity of 4.44 ± 0.18 U/mg dry cells, one of the highest transfructosylating activities thus far reported for whole-cell biocatalyst. Under optimal conditions (pH 5.5 and 55 °C), only 5 g/L of dry cells and 3 h reaction time were required to achieve a FOS yield of 61 % from 50 % (w/v) sucrose. Incubation of sugarcane molasses with an invertase-free Saccharomyces cerevisiae prior to addition of A. pullulans whole-cell biocatalyst eliminated glucose inhibition and increased FOS yield from 44 % to 56 % in 1 h. This study has demonstrated that the novel A. pullulans FRR 5284 was an efficient source of whole-cell biocatalyst for FOS production and a promising strategy for transformation of sucrose and sugarcane molasses into a higher-value prebiotic.