title: Effects of propionic acid and pH on ethanol fermentation by Saccharomyces cerevisiae in cassava mash.
abstract: The effects of propionic acid on ethanol and glycerol production by Saccharomyces cerevisiae in cassava mash were examined along with the influence of pH (4.0, 5.0, and 6.0) and of dissolved solids content (22%, 25%, and 27%). Inhibition by propionic acid increased as solids content increased and medium pH declined. Complete inhibition of ethanol fermentation was observed in mashes at pH 4.0 (60 mM propionic acid for 22% solids and 45 mM for 25% and 27%). Glycerol production linearly decreased with increased undissociated propionic acid concentration in all mashes at all pH levels, which partly contributed to increased final ethanol production when propionic acid concentration in mashes was low (≤ 30 mM).
authors.affiliation: The Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi 214122, China.
authors.forename: Cheng-Ming
authors.initials: CM
authors.lastname: Zhang
authors.forename: Li
authors.initials: L
authors.lastname: Jiang
authors.forename: Zhong-Gui
authors.initials: ZG
authors.lastname: Mao
authors.forename: Jian-Hua
authors.initials: JH
authors.lastname: Zhang
authors.forename: Lei
authors.initials: L
authors.lastname: Tang
mesh_terms: D056804:Biofuels; D018533:Biomass; D019149:Bioreactors; D000431:Ethanol / Q000378:metabolism*; D005285:Fermentation; D005990:Glycerol / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D006868:Hydrolysis; D007218:Industrial Microbiology / Q000379:methods*; D002365:Manihot / Q000378:metabolism*; D011422:Propionates / Q000737:chemistry* / Q000494:pharmacology; D012441:Saccharomyces cerevisiae / Q000187:drug effects / Q000201:enzymology; D013213:Starch / Q000378:metabolism*
chemical_list: D056804:Biofuels; D011422:Propionates; D000431:Ethanol; D013213:Starch; C029658:propionic acid; D005990:Glycerol