Optimization of bioconversion process for trehalose production from enzymatic hydrolysis of kudzu root starch using a visualization method

Background: Trehalose has many advantages due to its inertness and the ability to stabilize biomolecules. Trehalose synthase can catalyze intramolecular rearrangement of the inexpensive maltose into trehalose in a single step, which represents a simple, fast, and low-cost method for the future industrial production of trehalose. Results: In this work, an intelligent visualization method for producing trehalose via trehalose synthase was for the first time established and optimized by corresponding enzymatic hydrolysis with kudzu root starch as the initial raw material. For the first step, kudzu root starch was liquefied by α-amylase at a certain dextrose equivalent value of 19–21, and β-amylase and pullulanase to saccharify for a certain time, a four-factor nine-level experimental design with nine experiments was performed according to the uniform design table U^*₉(9⁴) to optimize the yield of maltose. Then, optimization of trehalose conversion ratio from kudzu root starch hydrolysate was carried out with a four-factor 12-level experimental design to forecast the optimal process conditions. By comparing verification tests and predicted results, the optimized operating conditions were pH 7.1, 22 °C, 32.5 % (14,000 U/ml) loading amounts of TreS enzyme and after 24 h, along with a 70.6 % trehalose conversion rate. Conclusions: The intelligent visualization method has succeeded in exploiting the conversion process of trehalose from kudzu root starch hydrolysate, which contributes significant benefits to the further commercial production of trehalose.