High‐titer biosynthesis of hyaluronic acid by recombinant Corynebacterium glutamicum |
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| Authors: | Fangyu Cheng Qianying Gong Huimin Yu Gregory Stephanopoulos |
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| Affiliation: | 1. Key Laboratory for Industrial Biocatalysis of the Ministry of Education, Department of Chemical Engineering, Tsinghua University, Beijing, China;2. College of Life Science and Technology, Beijing University of Chemical Technology, Beijing, China;3. Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA |
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| 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. |
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| Keywords: | Corynebacterium glutamicum Hyaluronic acid biosynthesis Inducible promoter Operon organization Synthetic pathway |
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