Comparative evaluation of glucose and ethanol yield from Icacina trichantha oliv and Anchomanes difformis blumel as non-edible feedstocks

This work examined the comparative potential of starch and flour obtained from two non-edible tuberous plants Anchomanes difformis blume (ADB) and Icacina trichantha oliv (ITO) for glucose and bioethanol production. Acid hydrolysis using sulfuric and hydrochloric acids, alongside enzymatic hydrolysis using α-amylase and amyloglucosidase, was employed to convert the biomass into fermentable sugars. The optimal glucose yield from acid hydrolysis was recorded with 0.25 M sulfuric acid at 120 °C for 45 minutes, with ADB starch yielding 28.41 g/L, the flour yielded 20.69 g/L and ITO starch yielding 22.09 g/L while flour yielded 20.42g/L. Fermentation using Saccharomyces cerevisiae showed maximum ethanol yields of 9.6 g/L and 8.92 g/L from ADB and ITO, respectively. While starch samples consistently yielded higher glucose and ethanol concentrations, flour samples demonstrated greater economic efficiency due to reduced processing requirements and higher net output per gram of raw biomass. Enzymatic hydrolysis further enhanced yields, with ADB and ITO achieving up to 26.09 g/L and 23.62 g/L ethanol, respectively. Overall, both ADB and ITO, particularly in flour form, offer viable alternatives to conventional starch feedstocks for sustainable bioethanol production.