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Bioconversion of wheat straw to ethanol: Chemical modification, enzymatic hydrolysis, and fermentation
Author(s) -
Detroy R. W.,
Lindenfelser L. A.,
Sommer S.,
Orton W. L.
Publication year - 1981
Publication title -
biotechnology and bioengineering
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.136
H-Index - 189
eISSN - 1097-0290
pISSN - 0006-3592
DOI - 10.1002/bit.260230712
Subject(s) - chemistry , hemicellulose , cellulase , fermentation , xylose , enzymatic hydrolysis , bioconversion , hydrolysis , straw , cellulosic ethanol , cellulose , sugar , food science , nuclear chemistry , biochemistry , inorganic chemistry
Abstract Native wheat straw (WS) was pretreated with various concentrations of H 2 SO 4 and NaOH followed by secondary treatments with ethylene diamine (EDA) and NH 4 OH prior to enzymatic saccharification. Conversion of the cellulosic component to sugar varied with the chemical modification steps. Treatment solely with alkali yield 51–75% conversion, depending on temperature. Acid treatment at elevated tempeatures showed a substantial decrease in the hemicellulose component, whereas EDA‐treated WS (acid pretreated) showed a 69–75% decrease in the lignin component. Acid‐pretreated EDA‐treated straw yielded a 98% conversion rate, followed by 83% for alkali–NH 4 OH treated straws. In other experiments, WS was pretreated with varying concentration of H 2 SO 4 or NaOh followed by NH 4 OH treatment prior to enzymatic hydrolysis. Pretreatment of straw with 2% NaOH for 4 h coupled to enzymatic hydrolysis yield a 76% conversion of the cellulosic component. Acid–base combination pretreatment yielded only 43% conversions. A reactor column was subsequently used to measure modification–saccharification–fermentation for wheat straw conversion on a larger scale. Thirty percent conversions of wheat straw cellulosics to sugar were observed with subsequent fermentation to alcohol. The crude cellulase preparation yielded considerable quantities of xylose in addition to the glucose. Saccharified materials were fermented directly with actively proliferating proliferating yeast cells without concentration of the sugars.