Main content area

Mild-temperature dilute acid pretreatment for integration of first and second generation ethanol processes

Nair, Ramkumar B., Kalif, Mahdi, Ferreira, Jorge A., Taherzadeh, Mohammad J., Lennartsson, Patrik R.
Bioresource technology 2017 v.245 pp. 145-151
Neurospora, energy, ethanol, fermentation, glucans, glucose, heat, lignin, lignocellulose, models, sawdust, wastes, wheat bran
The use of hot-water (100°C) from the 1st generation ethanol plants for mild-temperature lignocellulose pretreatment can possibly cut down the operational (energy) cost of 2nd generation ethanol process, in an integrated model. Dilute-sulfuric and -phosphoric acid pretreatment at 100°C was carried out for wheat bran and whole-stillage fibers. Pretreatment time and acid type influenced the release of sugars from wheat bran, while acid-concentration was found significant for whole-stillage fibers. Pretreatment led up-to 300% improvement in the glucose yield compared to only-enzymatically treated substrates. The pretreated substrates were 191–344% and 115–300% richer in lignin and glucan, respectively. Fermentation using Neurospora intermedia, showed 81% and 91% ethanol yields from wheat bran and stillage-fibers, respectively. Sawdust proved to be a highly recalcitrant substrate for mild-temperature pretreatment with only 22% glucose yield. Both wheat bran and whole-stillage are potential substrates for pretreatment using waste heat from the 1st generation process for 2nd generation ethanol.