title: Integrated hydrolyzation and fermentation of sugar beet pulp to bioethanol.
abstract: Sugar beet pulp is an abundant industrial waste material that holds a great potential for bioethanol production owing to its high content of cellulose, hemicelluloses, and pectin. Its structural and chemical robustness limits the yield of fermentable sugars obtained by hydrolyzation and represents the main bottleneck for bioethanol production. Physical (ultrasound and thermal) pretreatment methods were tested and combined with enzymatic hydrolysis by cellulase and pectinase to evaluate the most efficient strategy. The optimized hydrolysis process was combined with a fermentation step using a Saccharomyces cerevisiae strain for ethanol production in a single-tank bioreactor. Optimal sugar beet pulp conversion was achieved at a concentration of 60 g/l (39% of dry weight) and a bioreactor stirrer speed of 960 rpm. The maximum ethanol yield was 0.1 g ethanol/g of dry weight (0.25 g ethanol/g total sugar content), the efficiency of ethanol production was 49%, and the productivity of the bioprocess was 0.29 g/l·h, respectively.
authors.affiliation: Faculty of Food Technology and Biotechnology, University of Zagreb University, 10000 Zagreb, Pierottijeva 6, Croatia.
authors.forename: Tonči
authors.initials: T
authors.lastname: Rezić
authors.forename: Damir
authors.initials: D
authors.lastname: Oros
authors.forename: Iva
authors.initials: I
authors.lastname: Marković
authors.forename: Daniel
authors.initials: D
authors.lastname: Kracher
authors.forename: Roland
authors.initials: R
authors.lastname: Ludwig
authors.forename: Božidar
authors.initials: B
authors.lastname: Santek
mesh_terms: D027461:Beta vulgaris / Q000737:chemistry / Q000378:metabolism / Q000382:microbiology*; D056804:Biofuels / Q000032:analysis; D019149:Bioreactors / Q000382:microbiology; D000431:Ethanol / Q000378:metabolism*; D005285:Fermentation; D006868:Hydrolysis; D012441:Saccharomyces cerevisiae / Q000378:metabolism*; D014866:Waste Products / Q000032:analysis
chemical_list: D056804:Biofuels; D014866:Waste Products; D000431:Ethanol