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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.