Comparison of vacuum and high pressure evaporated wood hydrolyzate for ethanol production by repeated fed-batch using flocculating Saccharomyces cerevisiae
2009 (English)In: BioResources, E-ISSN 1930-2126, Vol. 4, no 1, p. 309-320Article in journal (Refereed) Published
Abstract [en]
Comparison of vacuum and high pressure evaporated wood hydrolyzate for ethanol production by repeated fed-batch using flocculating Saccharomyces cerevisiae
Abstract [en]
With the aim of increasing the sugars concentration in dilute-acid lignocellulosic hydrolyzate to more than 100 g/l for industrial applications, the hydrolyzate from spruce was concentrated about threefold by high-pressure or vacuum evaporations. It was then fermented by repeated fed-batch cultivation using flocculating Saccharomyces cerevisiae with no prior detoxification. The sugars and inhibitors concentrations in the hydrolyzates were compared after the evaporations and also fermentation. The evaporations were carried out either under vacuum (VEH) at 0.5 bar and 80 degrees C or with 1.3 bar pressure (HPEH) at 107.5 degrees C, which resulted in 153.3 and 164.6 g/l total sugars, respectively. No sugar decomposition occurred during either of the evaporations, while more than 96% of furfural and to a lesser extent formic and acetic acids disappeared from the hydrolyzates. However, HMF and levulinic acid remained in the hydrolyzates and were concentrated proportionally. The concentrated hydrolyzates were then fermented in a 4 l bioreactor with 12-22 g/l yeast and 0.14-0.22 h(-1) initial dilute rates (ID). More than 84% of the fermentable sugars present in the VEH were fermented by fed-batch cultivation using 12 g/l yeast and initial dilution rate (ID) of 0.22 h(-1), and resulted in 0.40+/-0.01 g/g ethanol from the fermentable sugars in one cycle of fermentation. Fermentation of HPEH was as successful as VEH and resulted in more than 86% of the sugar consumption under the corresponding conditions. By lowering the initial dilution rate to 0.14 h(-1), more than 97% of the total fermentable sugars were consumed, and ethanol yield was 0.44+/-0.01 g/g in one cycle of fermentation. The yeast was able to convert or assimilate HMF, levulinic, acetic, and formic acids by 96, 30, 43, and 74%, respectively.
Place, publisher, year, edition, pages
North Carolina State University , 2009. Vol. 4, no 1, p. 309-320
Keywords [en]
chitin, glucosamine, ethanol, biomass, biogas, lignocelluloses, baker's yeast, saccharomyces, cerevisiae, encapsulation, flocculation, superabsorbents, chitosan, zygomycetes, mucor, rhizopus, rhizomucor, MTBE, biopolymers, furfural, acetic acid, HMF, fed-batch, continuous cultivation, immobilization, denitrification, activated sludge, bread, orange peels, citrus, waste, keratin, methyl tertiary butyl ether
Keywords [sv]
Energi och material
National Category
Other Industrial Biotechnology
Identifiers
URN: urn:nbn:se:hb:diva-2577Local ID: 2320/4832OAI: oai:DiVA.org:hb-2577DiVA, id: diva2:870671
2015-11-132015-11-132024-07-04Bibliographically approved