Impact of ball milling on maize (Zea mays L.) stem structural components and on enzymatic hydrolysis of carbohydrates

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Journal Title
Journal ISSN
Volume Title
School of Chemical Technology | A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
Date
2014
Major/Subject
Mcode
Degree programme
Language
en
Pages
130-136
Series
Industrial Crops and Products, Volume 61
Abstract
The impact of ball milling on structural components of maize (Zea mays L.) stem was investigated in relation to enzymatic hydrolysis of carbohydrates. Ball milling of extractive-free maize stem material was carried out with different milling times up to 12 h. Carbohydrate conversion from ball-milled maize stem material with cellulolytic preparation Onozuka R-10 increased to 79% with increasing ball milling time up to 4 h, but did not thereafter increase further. Ball milling caused drastic depolymerization of hemicelluloses as revealed by increasing amounts of monosaccharides released in absence of enzymes. Infrared spectroscopy showed that cellulose crystallinity decreased within the first 6 h milling thereafter reaching a plateau. Thioacidolysis of solid residue fractions obtained after treatment of ball-milled samples with Onozuka R-10 suggested that no extensive degradation of lignin occurred during the milling. The effect of lignin structure on enzymatic hydrolysis of associated carbohydrates was further studied independently of cellulose crystallinity. Two lignin-carbohydrate fractions comprising hemicellulose and lignin with either high or low amount of aryl ether linkages were used as model materials. Lignins abundant in aryl ether linkages appeared more detrimental than condensed lignins to enzymatic hydrolysis of associated carbohydrates.
Description
Keywords
Ball milling, maize stem, stalk, lignocellulose, enzymatic, hydrolysis, lignin, structure
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Citation
Sipponen, Mika Henrikki & Laakso, Simo & Baumberger, Stéphanie. 2014. Impact of ball milling on maize (Zea mays L.) stem structural components and on enzymatic hydrolysis of carbohydrates. Industrial Crops and Products. Volume 61. P. 130-136. ISSN 0926-6690 (printed). DOI: 10.1016/j.indcrop.2014.06.052.