title: Pilot scale demonstration of D-lactic acid fermentation facilitated by Ca(OH)2 using a metabolically engineered Escherichia coli.
abstract: In this study, a genetically engineered Escherichia coli strain, HBUT-D (ΔpflB Δpta ΔfrdABCD ΔadhE Δald ΔcscR), was initially evaluated on a laboratory scale (7 L) in a glucose (130 g L(-1)) mineral salts medium for d-lactic acid fermentation using 6N KOH, Ca(OH)2 or NH4OH as the neutralizing agent. Fermentations neutralized by Ca(OH) 2 achieved a volumetric productivity of 6.35 g L(-1) h(-1), tripling that achieved by KOH (1.71 g L(-1) h(-1)) and NH4OH (1.5 g L(-1) h(-1)). The facilitative effect of Ca(OH)2 neutralization was then demonstrated on a pilot scale (6 ton vessel, 130 kg glucose ton(-1)), resulting in a volumetric productivity of 6 kg ton(-1) h(-1), a titer of 126 kg ton(-1), a yield of 97%, and an optical purity of 99.5%. These results demonstrated that E. coli HBUT-D is a promising strain for large scale d-lactic acid fermentation using mineral salts medium and Ca(OH)2 for neutralization.
authors.affiliation: Hubei Provincial Cooperative Innovation Center of Industrial Fermentation, Key Laboratory of Fermentation Engineering (Ministry of Education), College of Bioengineering, Hubei University of Technology, Wuhan 430068, PR China.
authors.forename: Ye
authors.initials: Y
authors.lastname: Liu
authors.affiliation: Hubei Provincial Cooperative Innovation Center of Industrial Fermentation, Key Laboratory of Fermentation Engineering (Ministry of Education), College of Bioengineering, Hubei University of Technology, Wuhan 430068, PR China. Electronic address: wgao@mail.hbut.edu.cn.
authors.forename: Wa
authors.initials: W
authors.lastname: Gao
authors.affiliation: Hubei Provincial Cooperative Innovation Center of Industrial Fermentation, Key Laboratory of Fermentation Engineering (Ministry of Education), College of Bioengineering, Hubei University of Technology, Wuhan 430068, PR China.
authors.forename: Xiao
authors.initials: X
authors.lastname: Zhao
authors.affiliation: Hubei Provincial Cooperative Innovation Center of Industrial Fermentation, Key Laboratory of Fermentation Engineering (Ministry of Education), College of Bioengineering, Hubei University of Technology, Wuhan 430068, PR China.
authors.forename: Jinhua
authors.initials: J
authors.lastname: Wang
authors.affiliation: Department of Biological Sciences, Northern Illinois University, DeKalb, IL 60115, USA.
authors.forename: Erin
authors.initials: E
authors.lastname: Garza
authors.affiliation: Hubei Provincial Cooperative Innovation Center of Industrial Fermentation, Key Laboratory of Fermentation Engineering (Ministry of Education), College of Bioengineering, Hubei University of Technology, Wuhan 430068, PR China; Department of Biological Sciences, Northern Illinois University, DeKalb, IL 60115, USA.
authors.forename: Ryan
authors.initials: R
authors.lastname: Manow
authors.affiliation: Hubei Provincial Cooperative Innovation Center of Industrial Fermentation, Key Laboratory of Fermentation Engineering (Ministry of Education), College of Bioengineering, Hubei University of Technology, Wuhan 430068, PR China; Department of Biological Sciences, Northern Illinois University, DeKalb, IL 60115, USA. Electronic address: szhou@niu.edu.
authors.forename: Shengde
authors.initials: S
authors.lastname: Zhou
mesh_terms: D055162:Biocatalysis / Q000187:drug effects; D002126:Calcium Hydroxide / Q000494:pharmacology*; D003362:Cost-Benefit Analysis; D004926:Escherichia coli / Q000187:drug effects / Q000378:metabolism*; D005285:Fermentation / Q000187:drug effects*; D019344:Lactic Acid / Q000378:metabolism*; D060847:Metabolic Engineering / Q000191:economics / Q000379:methods*; D010865:Pilot Projects
chemical_list: D019344:Lactic Acid; D002126:Calcium Hydroxide
keywords: Ca(OH)(2); Escherichia coli; Neutralization; PLA; d-Lactic acid