title: Two-Step Production of Phenylpyruvic Acid from L-Phenylalanine by Growing and Resting Cells of Engineered Escherichia coli: Process Optimization and Kinetics Modeling.
abstract: Phenylpyruvic acid (PPA) is widely used in the pharmaceutical, food, and chemical industries. Here, a two-step bioconversion process, involving growing and resting cells, was established to produce PPA from l-phenylalanine using the engineered Escherichia coli constructed previously. First, the biotransformation conditions for growing cells were optimized (l-phenylalanine concentration 20.0 g·L-1, temperature 35°C) and a two-stage temperature control strategy (keep 20°C for 12 h and increase the temperature to 35°C until the end of biotransformation) was performed. The biotransformation conditions for resting cells were then optimized in 3-L bioreactor and the optimized conditions were as follows: agitation speed 500 rpm, aeration rate 1.5 vvm, and l-phenylalanine concentration 30 g·L-1. The total maximal production (mass conversion rate) reached 29.8 ± 2.1 g·L-1 (99.3%) and 75.1 ± 2.5 g·L-1 (93.9%) in the flask and 3-L bioreactor, respectively. Finally, a kinetic model was established, and it was revealed that the substrate and product inhibition were the main limiting factors for resting cell biotransformation.
authors.affiliation: Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, Jiangnan University, Wuxi 214122, China.|Synergetic Innovation of Center of Food Safety and Nutrition, Jiangnan University, Wuxi 214122, China.
authors.forename: Ying
authors.initials: Y
authors.lastname: Hou
authors.affiliation: Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, Jiangnan University, Wuxi 214122, China.|Synergetic Innovation of Center of Food Safety and Nutrition, Jiangnan University, Wuxi 214122, China.
authors.forename: Gazi Sakir
authors.initials: GS
authors.lastname: Hossain
authors.affiliation: Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, Jiangnan University, Wuxi 214122, China.|Synergetic Innovation of Center of Food Safety and Nutrition, Jiangnan University, Wuxi 214122, China.
authors.forename: Jianghua
authors.initials: J
authors.lastname: Li
authors.affiliation: School of Chemical and Biomolecular Engineering, Georgia Institute of Technology, Atlanta 30332, Georgia, United States of America.
authors.forename: Hyun-Dong
authors.initials: HD
authors.lastname: Shin
authors.affiliation: Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, Jiangnan University, Wuxi 214122, China.|Synergetic Innovation of Center of Food Safety and Nutrition, Jiangnan University, Wuxi 214122, China.
authors.forename: Long
authors.initials: L
authors.lastname: Liu
authors.affiliation: Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, Jiangnan University, Wuxi 214122, China.|Synergetic Innovation of Center of Food Safety and Nutrition, Jiangnan University, Wuxi 214122, China.
authors.forename: Guocheng
authors.initials: G
authors.lastname: Du
authors.affiliation: Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, Jiangnan University, Wuxi 214122, China.|Synergetic Innovation of Center of Food Safety and Nutrition, Jiangnan University, Wuxi 214122, China.
authors.forename: Jian
authors.initials: J
authors.lastname: Chen
mesh_terms: D019149:Bioreactors / Q000382:microbiology; D001711:Biotransformation / Q000187:drug effects; D004926:Escherichia coli / Q000187:drug effects / Q000254:growth & development* / Q000378:metabolism*; D005818:Genetic Engineering / Q000379:methods*; D007700:Kinetics; D008954:Models, Biological; D010100:Oxygen / Q000494:pharmacology; D010649:Phenylalanine / Q000378:metabolism*; D010667:Phenylpyruvic Acids / Q000378:metabolism*; D013379:Substrate Specificity / Q000187:drug effects; D013997:Time Factors
chemical_list: D010667:Phenylpyruvic Acids; D010649:Phenylalanine; D010100:Oxygen; C031606:phenylpyruvic acid