Ethanol production from non-starch carbohydrates of wheat bran.
Wheat bran (WB), produced worldwide in large quantities as a by-product of the wheat milling industry, constitutes a significant underutilized source of sugars. This paper describes various methods of hydrolyzing the abundant polysaccharides in bran to yield a sugar feedstock suitable for fermentation into bioethanol. Firstly, the starch in the bran was released using amylolytic enzymes. The fibrous material remaining was further hydrolyzed. Acid hydrolysis, heat pretreatment followed by enzymatic hydrolysis and direct enzymatic hydrolysis were compared in terms of total sugar yield and pentose sugar yield. The maximum total sugar yield was achieved when small amounts of acid were added at the pretreatment step prior to enzymatic hydrolysis. This form of pretreatment released most pentosans and significantly enhanced the hydrolysis of cellulose. The overall sugar yield of this combined hydrolysis method reached 80% of the theoretical and it consisted of 13.5 g arabinose, 22.8 g xylose and 16.7 g glucose per 100 g starch-free bran.
Palmarola-Adrados
Beatriz
B
Department of Chemical Engineering, Lund University, P.O. Box 124, SE-221 00 Lund, Sweden.
Choteborská
Pavla
P
Galbe
Mats
M
Zacchi
Guido
G
D050260:Carbohydrate Metabolism; D002241:Carbohydrates / Q000737:chemistry; D004798:Enzymes / Q000737:chemistry / Q000378:metabolism; D000431:Ethanol / Q000737:chemistry / Q000378:metabolism*; D005285:Fermentation; D005525:Food-Processing Industry / Q000379:methods*; D006868:Hydrolysis; D013213:Starch; D013464:Sulfuric Acids / Q000737:chemistry / Q000378:metabolism; D013696:Temperature; D014908:Triticum / Q000737:chemistry* / Q000378:metabolism
D002241:Carbohydrates; D004798:Enzymes; D013464:Sulfuric Acids; D000431:Ethanol; D013213:Starch; C033158:sulfuric acid