Open AccessEthanol production from grass silage by simultaneous pretreatment, saccharification and fermentation: First steps in the process development
Author(s) -
Sieker Tim,
Neuner Andreas,
Dimitrova Darina,
Tippkötter Nils,
Muffler Kai,
Bart HansJörg,
Heinzle Elmar,
Ulber Roland
Publication year - 2011
Publication title -
engineering in life sciences
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.547
H-Index - 57
eISSN - 1618-2863
pISSN - 1618-0240
DOI - 10.1002/elsc.201000160
Subject(s) - silage , fermentation , chemistry , ethanol fuel , food science , hydrolysis , biofuel , ethanol , raw material , enzymatic hydrolysis , agronomy , pulp and paper industry , biochemistry , microbiology and biotechnology , organic chemistry , biology , engineering
Grass silage provides a great potential as renewable feedstock. Two fractions of the grass silage, a press juice and the fiber fraction, were evaluated for their possible use for bioethanol production. Direct production of ethanol from press juice is not possible due to high concentrations of organic acids. For the fiber fraction, alkaline peroxide or enzymatic pretreatment was used, which removes the phenolic acids in the cell wall. In this study, we demonstrate the possibility to integrate the enzymatic pretreatment with a simultaneous saccharification and fermentation to achieve ethanol production from grass silage in a one‐process step. Achieved yields were about 53 g ethanol per kg silage with the alkaline peroxide pretreatment and 91 g/kg with the enzymatic pretreatment at concentrations of 8.5 and 14.6 g/L, respectively. Furthermore, it was shown that additional supplementation of the fermentation medium with vitamins, trace elements and nutrient salts is not necessary when the press juice is directly used in the fermentation step.