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Conversion of cassava starch to ethanol and a byproduct under different hydrolysis conditions
Author(s) -
Mayer Flávio Dias,
Gasparotto Juliana Machado,
Klauck Evelin,
Werle Leandro Bernardi,
Jahn Sergio Luiz,
Hoffmann Ronaldo,
Mazutti Marcio Antônio
Publication year - 2015
Publication title -
starch ‐ stärke
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.62
H-Index - 82
eISSN - 1521-379X
pISSN - 0038-9056
DOI - 10.1002/star.201500043
Subject(s) - starch , hydrolysis , fermentation , chemistry , enzymatic hydrolysis , amylase , food science , ethanol , yield (engineering) , ethanol fuel , residue (chemistry) , liquefaction , alpha amylase , enzyme , biochemistry , organic chemistry , materials science , metallurgy
Cassava starch can be converted into sugars by enzymatic hydrolysis to be used for ethanol production. In this work, the studied variables were starch and enzymes concentration seeking a higher conversion of the reducing sugars routine. Two series of experiments were conducted following the steps of gelatinization, liquefaction, and saccharification, ending with the fermentation step. It was found that a 100–250 times increase in α‐amylase concentration results in a 23% increase in the starch yield. Therefore, an optimal enzyme concentration could be found. The glucoamylase enzyme has proved to be more effective, evaluated by the rate of starch conversion ( k ), at a lower concentration of starch (10%), and enzyme (10 U/g). In simultaneous saccharification and fermentation (SSF), the hydrolysis yield was 33% higher than in a conventional process, achieving efficiencies higher than 70%. The solid residue separated after the SSF process proved to be a high‐quality animal feed additive.