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

Da Wang, Fu-Li Li, Shi-An Wang

Shandong Provincial Key Laboratory of Synthetic Biology, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao 266101, China.

Abstract

Commercial fructo-oligosaccharides (FOS) are predominantly produced from sucrose by transfructosylation process that presents a maximum theoretical yield below 0.60 g_FOS g_Sucrose^-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 g_FOS g_Inulin^-1, and 7.51 ± 0.03 g/L/h, respectively. This study demonstrated that the one-step bioprocess was simple and highly efficient.

Keywords: Fructo-oligosaccharides; Inulin; One-step bioprocess; Yeast.