Taxonomic group: bacteria / Proteobacteria
(Phylum: Proteobacteria)
NCBI PubMed ID: 35631877Publication DOI: 10.3390/polym14101994Journal NLM ID: 101545357Publisher: Basel: MDPI
Correspondence: C. Delbarre-Ladrat <christine.delbarre.ladrat
ifremer.fr>
Institutions: Ifremer, MASAE, EM3B Laboratory, CEDEX 3, F-44300 Nantes, France
Recent advances in glycobiotechnology show that bacterial exopolysaccharides (EPS) presenting glycosaminoglycan (GAG)-like properties can provide a valuable source of bio-active macromolecules for industrial applications. The HE800 EPS, named diabolican, is a marine-derived anionic high-molecular-weight polysaccharide produced by Vibrio diabolicus CNCM I-1629 which displays original structural features close to those of hyaluronic acid. We investigated the impact of carbon and nitrogen substrates on both Vibrio diabolicus growth and diabolican production. Both substrates were screened by a one-factor-at-a-time method, and experimental designs were used to study the effect of glucose, mannitol, and ammonium acetate various concentrations. Results showed that the medium composition affected not only the bacterium growth and EPS yield, but also the EPS molecular weight (MW). EPS yields of 563 and 330 mg L-1 were obtained in the presence of 69.3 g L-1 glucose and 24.6 g L-1 mannitol, respectively, both for 116.6 mM ammonium acetate. MW was the highest, with 69.3 g L-1 glucose and 101.9 mM ammonium acetate (2.3 × 106 g mol-1). In parallel, the bacterial maximum specific growth rate was higher when both carbon and nitrogen substrate concentrations were low. This work paves the way for the optimization of marine exopolysaccharide production of great interest in the fields of human health and cosmetics.
exopolysaccharide, production, molecular weight, Marine bacterium, central composite design, Vibrio diabolicus, yield
Structure type: polymer chemical repeating unit ; 800000
Location inside paper: p. 1994-1
Trivial name: diabolican
Compound class: EPS, polysaccharide
Contained glycoepitopes: IEDB_115136,IEDB_130648,IEDB_135813,IEDB_137340,IEDB_137473,IEDB_1391961,IEDB_140630,IEDB_141584,IEDB_141807,IEDB_151531,IEDB_423153,IEDB_885822
Methods: composition analysis, HPLC, HPSEC, GC-FID, MALS, OD, selection medium, cultivation, EPS production, RI
NCBI Taxonomy refs (TaxIDs): 50719Reference(s) to other database(s): GTC:G62612LA
Show glycosyltransferases
There is only one chemically distinct structure:
Taxonomic group: bacteria / Firmicutes
(Phylum: Firmicutes)
Associated disease: infection due to Bacillus subtilis [ICD11:
XM4SG9 
]
The structure was elucidated in this paperNCBI PubMed ID: 33142650Publication DOI: 10.1016/j.carbpol.2020.117115Journal NLM ID: 8307156Publisher: Elsevier
Correspondence: jinpeng
zafu.edu.cn; qizhendu
163.com
Institutions: College of Agricultural and Food Sciences, Zhejiang A & F University, Hangzhou, 311300, China, Technology Center of Haikou Customs District China, Haikou 570311, China, Institute of Microbial Engineering, Henan University, Kaifeng, China
Mannans are functional polysaccharides with unique biological activities that have been employed widely in food, medicine and pharmaceutics. Recent breakthroughs in plant polysaccharide metabolism identified numerous genes involved in the biosynthesis of mannans. However, constructing highly efficient low-cost microbial cell factories to produce low-molecular-weight (LMW) mannans remains challenging. In this work, we designed a de novo mannan synthetic pathway in food-grade Bacillus subtilis, resulting in mannan accumulation of 0.97 g/L. By co-expressing the identified committed genes (manC, manB, manA and pgi), mannan production was significantly increased to 2.5 g/L. Furthermore, by redirecting the carbon flux using a glucose-repressed promoter to control pfkA expression, mannan production was substantially increased to 4.1 g/L. Production was further enhanced to 12.6 g/L (average MW 6370 Da) in 3-L fed-batch fermentation. This work provides alternative synthetic pathways for metabolic engineering of LMW mannans in B. subtilis, and a useful, optimisable approach to enhance mannans production.
Bacillus subtilis, Metabolic engineering, De novosynthetic pathway, functional polysaccharide, low-molecular-weight mannan, redirecting carbon flux
Structure type: homopolymer ; 6370
Location inside paper: Fig. 2, p. 117115-7, Fig. S2
Trivial name: mannan
Compound class: EPS
Contained glycoepitopes: IEDB_137485,IEDB_140116,IEDB_144983,IEDB_152206,IEDB_76920,IEDB_983930,SB_44,SB_72
Methods: GC-MS, FTIR, biochemical methods, RT-PCR, glycoengineering, DNA manipulation, HPLC-GPC-RI, OD
Biosynthesis and genetic data: pgi, manA, manB, manC, ctmanS
NCBI Taxonomy refs (TaxIDs): 1423
Show glycosyltransferases
There is only one chemically distinct structure:
Found 
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