Enhanced Succinic Acid Production in Escherichia coli by Model-Guided Metabolic Gene Knockout of pflA Using Glucose Carbon Source Research Article Journal of Biotechnology & Bioresearch C CRIMSON PUBLISHERS Wings to the Research 1/7 Copyright © All rights are reserved by Bashir SajoMienda. Volume - 1 Issue - 1 Bashir Sajo Mienda 1 *,Saidu Jibril 2 , Umar Ali 3 , Aminu Muhammad 4 , Rabiu Salihu 1 and Aliyu Adamu 5 1 Department of Microbiology & Biotechnology, Federal University Dutse, Nigeria 2Department of Chemical Sciences, Federal University Kashere, Nigeria 3Department of Chemistry, SuleLamido University Kafin Hausa, Nigeria 4Department of Pure and Industrial Chemistry, Bayero University Kano, Nigeria 5Department of Microbiology, Kaduna State University, Nigeria *Corresponding author: Bashir SajoMienda, Department of Microbiology & Biotechnology, Faculty of Science, Federal University Dutse, PMB 7156 Ibrahim Aliyu Bypass, Dutse, Jigawa State, Nigeria Submission: May 30, 2018; Published: July 09, 2018 Abstract Succinic acid is an important platform and/or commodity or specialty chemical with a broad range of applications. The metabolic role of pyruvate formatelyase A (pflA) in relation to succinate production in Escherichia coli under anaerobic conditions from glucose substrate remained largely unspecified. Herein we identified pflAgene for the first time, as a novel gene knockout target for increasing succinate production in E. coli. Guided by E. coli reconstruction iJO1366, we engineered the E. coli host metabolism by deleting the pflA, thereby causing the up-regulation of glyceraldehyde- 3-phosphate dehydrogenase (GAPDH), which hypothetically increases the generation of NADH and the pool of phosphoenolpyruvate (PEP) in the central carbon metabolism, required for succinate production. This strategy produced succinic acid that is 4.78 fold (0.28g l-1 in 1day) from glucose substrate. This work elucidatesfor the first time that pflA is a novel gene deletion target for increasing succinic acid production in E. coli under anaerobic conditions. In addition, these results highlight the power of metabolic model in identifying novel gene deletion target and ultimately driving novel biological discovery. Keywords: Escherichia coli genome-scale model;Metabolic gene knockout prediction;Pyruvate formatelyase (pflA); Glucose carbon source; Enhanced succinate production Introduction Microbial fermentation for succinic acid production has been pursued in recent time because it is considered cheaper and envi- ronmentally friendly approach than its petroleum based chemical production from maleic anhydride [1]. Recently, several bacteria, such as Anaero biospirillum succiniciproducens, Actinobacillus succinogenes and Mannheimia succiniciproducens have been es- tablished to produce succinic acid as a major fermentation product [2]. However, these strains require complex organic nutrients that increase the costs of productions, purifications and the waste dis- posal which ultimately add to process costs and complexity [2,3]. Escherichia coli have been known to naturally carry out mixed acid fermentation with succinic acid as a minor fermentation product among others. As a specialty and/or commodity chemical, succin- ic acid has invaluable applications, such as a precursor for various chemicals, including green solvents and biodegradable plastics, it can also be used as an iron chelator and a supplement to many foods and pharmaceuticals [1,2]. Succinic acid has also been list- ed by the U.S. Department of Energy (DOE) among the 12 top bio- based building block chemicals that can be produced by microbial fermentation [4,5]. Several numbers of metabolically engineered E. coli strains were constructed, with or without foreign genes for enhanced succinate production using glucose substrate [2]. While others, used mineral salt medium to produce succinate in meta- bolically engineered E. Colistrains by knocking out pyruvate for- matelyase B (pflB) [3]. pflB was previously designated as a formate acetyltransferase I, which its deletion under anaerobic conditions blocks formate formation and increase succinate production [3,6]. The disruption of pyruvate formatelyase (pfl) was established to increase D-lactate production in E. coli under micro-aerobic condi- tions [7]. The deletion of pflA for increasing succinic acid produc- tion has not yet been elucidated.