Ultrasonic and fermented pretreatment technology for diosgenin production from Diosorea zingiberensis C.H. Wright

The present study evaluated the efficiency of ultrasonic and fermented pretreatment technology for diosgenin production from Diosorea zingiberensis C.H. Wright (DZW). The optimum extraction conditions were as follows: ultrasonic pretreatment condition, 20 min, 50 kHz, 100 W; fermented pretreatment condition, 30 °C, 3 d and 0.8 g yeast dosages per 100 g raw materials; acidic hydrolysis condition, 1.5 mol/L sulfuric acid, 4 h; petrol extraction condition, 5 h. Under these conditions, diosgenin yield could reach 2.30%. Scanning electron micrographs indicated morphology changes of materials during diosgenin extraction process. UV–vis and GC–MS analysis revealed wastewater from the new approach contained 20 kinds of organic compounds which were mainly acids, esters, ketones and hydrocarbons. The research indicated the new approach could not only increase 42.5% diosgenin yield, recover 81.6% starch and 50.8% cellulose, but also efficiently reduce 69.7% COD, comparing with the conventional approach.

Research highlights▶ The new process increases 42.5% diosgenin yield, comparing with the conventional approach. ▶ The new process recovers 81.63% starch and 50.76% cellulose. ▶ The new process reduces 69.72% COD, comparing with the conventional approach. ▶ The organics of wastewater from the new process are less and easier to be degraded, comparing with the conventional approach.