Potential application of α-amylase from germinating cucurbita moschata duchesne seeds in eco-friendly bioethanol production.

The α-amylase from Cucurbita moschata Duchesne seeds (CmAmy) was purified using ammonium sulfate fractionation, followed by β-cyclodextrin sepharose 6B affinity chromatography. The enzyme exhibited a specific activity of 475.00 U/mg, resulting in a 208.54-fold and a 30.89% yield. The optimal pH and temperature for CmAmy were determined to be 7.0 and 60 °C, respectively. The enzyme demonstrated high stability across a temperature range of 40-80 °C and a pH range of 5-9. The CmAmy has been identified as an eco-friendly candidate for bioethanol production by utilizing cassava and rice waste. The optimal condition for sugar production through hydrolysis with CmAmy involved an enzyme concentration of 7.5 mU, a substrate concentration of 2.0% w/v, and a hydrolysis duration of 4 h for cassava waste. For rice waste, the optimal parameters consisted of an enzyme amount of 10 mU, a substrate concentration of 1.5% w/v, and a hydrolysis time of 3 h. The resulting sugars were fermented using Saccharomyces cerevisiae to yield bioethanol, achieving maximum concentrations of 19.6 g/L (0.98 g ethanol/g cassava waste) and 20.1 g/L (1.33 g ethanol/g rice waste) for cassava and rice waste, respectively. This investigation highlights the potential of CmAmy for eco-friendly bioethanol production, offering advantages of simplicity, cost-effectiveness, and sustainability.