title: High-titer biosynthesis of hyaluronic acid by recombinant Corynebacterium glutamicum.
abstract: Hyaluronic acid (HA) plays important roles in human tissue system, thus it is highly desirable for various applications, such as in medical, clinic and cosmetic fields. The wild microbial producer of HA, streptococcus, was restricted by its potential pathogens, hence different recombinant hosts are being explored. In this work, we engineered Corynebacterium glutamicum, a GRAS (Generally Recognized as Safe) organism free of exotoxins and endotoxins to produce HA with high titer and satisfied Mw . The ssehasA gene encoding hyaluronan synthase (HasA) was artificially synthesized with codon preference of C. glutamicum. Other genes involved in the HA synthetic pathway were directly cloned from the C. glutamicum genome. The operon structures and constitutive or inducible promoters were particularly compared and the preferred environmental conditions were also optimized. Using glucose and corn syrup powder as carbon and nitrogen sources, batch cultures of the engineered C.glutamicum with operon ssehasA-hasB driven by Ptac promoter were performed in a 5 L fermentor. The maximal HA titer, productivity and yield reached 8.3 g/L, 0.24 g/L/h and 0.22 gHA/gGlucose, respectively; meanwhile the maximal Mw was 1.30 MDa. This work provides a safe and efficient novel producer of HA with huge industrial prospects.
authors.affiliation: Key Laboratory for Industrial Biocatalysis of the Ministry of Education, Department of Chemical Engineering, Tsinghua University, Beijing, China.
authors.forename: Fangyu
authors.initials: F
authors.lastname: Cheng
authors.affiliation: College of Life Science and Technology, Beijing University of Chemical Technology, Beijing, China.
authors.forename: Qianying
authors.initials: Q
authors.lastname: Gong
authors.affiliation: Key Laboratory for Industrial Biocatalysis of the Ministry of Education, Department of Chemical Engineering, Tsinghua University, Beijing, China. yuhm@mail.tsinghua.edu.cn.
authors.forename: Huimin
authors.initials: H
authors.lastname: Yu
authors.affiliation: Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA. gregstep@mit.edu.
authors.forename: Gregory
authors.initials: G
authors.lastname: Stephanopoulos
mesh_terms: D061249:Batch Cell Culture Techniques; D048230:Corynebacterium glutamicum / Q000235:genetics / Q000254:growth & development*; D005285:Fermentation; D005818:Genetic Engineering; D005947:Glucose / Q000737:chemistry; D066248:High Fructose Corn Syrup / Q000737:chemistry; D006820:Hyaluronic Acid / Q000096:biosynthesis* / Q000235:genetics*; D009876:Operon
chemical_list: D066248:High Fructose Corn Syrup; D006820:Hyaluronic Acid; D005947:Glucose
keywords: Corynebacterium glutamicum; Hyaluronic acid biosynthesis; Inducible promoter; Operon organization; Synthetic pathway