A one-step bioprocess for production of high-content fructo-oligosaccharides from inulin by yeast

Commercial fructo-oligosaccharides (FOS) are predominantly produced from sucrose by transfructosylation process that presents a maximum theoretical yield below 0.60 gFOS gSucrose−1. To obtain high-content FOS, costly purification is generally employed. Additionally, high-content FOS can be produced from inulin by using endo-inulinases. However, commercial endo-inulinases have not been extensively used in scale-up production of FOS. In the present study, a one-step bioprocess that integrated endo-inulinase production, FOS fermentation, and non-FOS sugars removal into one reactor was proposed to produce high-content FOS from inulin. The bioprocess was implemented by a recombinant yeast strain JZHΔS-TSC, in which a heterologous endo-inulinase gene was expressed and the inherent invertase gene SUC2 was disrupted. FOS fermentation at 40 °C from 200 g/L chicory inulin presented the maximun titer, yield, and productivity of 180.2 ± 0.8 g/L, 0.9 gFOS gInulin−1, and 7.51 ± 0.03 g/L/h, respectively. This study demonstrated that the one-step bioprocess was simple and highly efficient.