New two-stage pH combined with dissolved oxygen control strategy for cyclic ß-1,2 glucans synthesis.
Appl Microbiol Biotechnol
; 107(7-8): 2235-2247, 2023 Apr.
Article
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| MEDLINE
| ID: mdl-36894714
ABSTRACT
On the basis of a novel two-stage pH combined with dissolved oxygen (DO) control strategy in fed-batch fermentation, this research addresses the influence of pH on cyclic ß-1,2-glucans (CßGs) biosynthesis and melanin accumulation during the production of CßGs by Rhizobium radiobacter ATCC 13,333. Under these optimal fermentation conditions, the maximum cell concentration and CßGs concentration in a 7-L stirred-tank fermenter were 7.94 g L-1 and 3.12 g L-1, which were the maximum production reported for R. radiobacter. The melanin concentration of the fermentation broth was maintained at a low level, which was beneficial to the subsequent separation and purification of the CßGs. In addition, a neutral extracellular oligosaccharide (COGs-1) purified by the two-stage pH combined with DO control strategy fermentation medium was structurally characterized. Structural analyses indicated that COGs-1 was a family of unbranched cyclic oligosaccharides composed of only ß-1,2-linked D-glucopyranose residues with degree of polymerization between 17 and 23, namely CßGs. This research provides a reliable source of CßGs and structural basis for further studies of biological activity and function. KEY POINTS ⢠A two-stage pH combined with DO control strategy was proposed for CßGs production and melanin biosynthesis by Rhizobium radiobacter. ⢠The final extracellular CßGs production reached 3.12 g L-1, which was the highest achieved by Rhizobium radiobacter. ⢠The existence of CßGs could be detected by TLC quickly and accurately.
Palabras clave
Texto completo:
1
Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Oxígeno
/
Melaninas
Idioma:
En
Revista:
Appl Microbiol Biotechnol
Año:
2023
Tipo del documento:
Article
País de afiliación:
China