Feasibility of producing butanol from industrial starchy food wastes

To evaluate the feasibility of using industrial starchy food wastes as alternative feedstocks for fermentative production of butanol, 34 different food waste samples were obtained from 10 major Ohio food manufacturing companies. Of the food waste samples, 8 were characterized for acetone butanol ethanol (ABE) production. The food waste samples were characterized for moisture, total solids, ash, nitrogen, total organic carbon (TOC), pH, calorific value, minerals and starch content. Results showed that the pH of inedible dough and breadings was in the acceptable substrate pH range (pH 6.2-7.4) for culturing solventogenic Clostridium species, whereas the pH of batter liquid was 4.5, hence, adjusted to pH 6.5 with NH4OH prior to fermentation. Further, batch fermentations by Clostridium beijerinckii NCIMB 8052 using inedible dough, breadings, and batter liquid as substrates generated the following maximum ABE concentrations: 14.4, 14.8 and 15.1 g/L ABE, respectively, which is comparable to the glucose control. Besides, the ABE yield from inedible dough and batter liquid was over 2% better than that of the glucose control. Collectively, these results demonstrate that industrial starchy food waste is a viable alternative substrate for butanol production.