10-47: Sequential thermochemical hydrolysis, enzymatic saccharification and fermentation to ethanol of stover from white corn with ethanologenic bacteria

Stover obtained from the harvest of white corn (S-WC) in Mexico was used to study the sequential thermochemical hydrolysis, enzymatic saccharification and fermentation of sugar mixtures to ethanol with the ethanologenic Escherichia coli MS04. All procedures were performed in the same stainless steel – glass vessel at a working volume of 500 mL. The stover, at an initial ratio of 1:6 (g of S-WC : 2% H₂SO₄), was pretreated at 130 ºC for 30 min; after cooling down, the pH was adjusted and the saccharification, with commercial enzymes, was performed using the whole slurry at 50 °C; then the pH of the syrup was adjusted to 6 and inoculated, at 37 °C, with the ethanologenic E. coli MS04: MG1655, ΔpflB, ΔadhE, ΔfrdA, ΔxylFGH, gatC S184L, ΔmidarpA, Δreg 27.3 kb, ΔldhA, PpflB::pdc_Zm-adhA_Zm. The mixture of sugars was fermented to 25 g/L of ethanol in 1 day.