Bioethanol production from waste hamburger by enzymatic hydrolysis and fermentation

Hamburger is one of the largest parts of fast food in the world. The feasibility of bioethanol production from waste hamburger (WH) by enzymatic hydrolysis (commercial alpha-amylase) and fermentation was investigated in this study. Different enzyme loading volumes (B1: 0.02 mL/L, B2: 0.08 mL/L and B3: 0.14 mL/L) were used to evaluate the hydrolysis efficiency. The maximum chemical oxygen demand of 74.2 g/L, reducing sugar (RS) of 39.2 g/L and hydrolysis efficiency of 0.784 g RS/g WH could be achieved with B3. The reduction rate of WH could reach 76.8%-80.4%. The ethanol fermentation could be finished within 50 h since the soluble nutrient pretreated by alpha-amylase was easy to be used by the yeast. The highest ethanol production of 27.4 g/L and ethanol yield of 0.271 g ethanol/g WH (0.34 g ethanol/g TS) were achieved with B3. The waste hamburger hydrolysate is a promising substrate for bioethanol production and has high potential for industrial application. (C) 2020 Elsevier Ltd. All rights reserved.