title: An increase of curdlan productivity by integration of carbon/nitrogen sources control and sequencing dual fed-batch fermentors operation.
abstract: Curdlan is produced by Agrobacterium sp. ATCC 31749 under nitrogen-limited conditions not associated with cell growth. A novel curdlan production process was developed based on the different nutrient requirements for microbial cell growth and its efficiency was increased by integrating carbon/nitrogen sources control and sequencing dual fed-batch fermentors operation. By feeding ammonium solution to supply abundant nitrogen source and controlling pH in Fermentor I, cell growth was accelerated. High cell density of 29 g/L was attained. The culture broth in Fermentor I was then inoculated into sequencing Fermentor II which alleviated the high requirement for dissolved oxygen and accumulation of inhibitory metabolic by-products during curdlan production. Fermentor I promoted cell growth. Curdlan production started instantaneously in Fermentor II. By feeding nutrient solution with high carbon/nitrogen ratio and NaOH solution for pH adjustment, a feasible and optimal curdlan production process was formulated. The productivity, conversion efficiency and curdlan yield were achieved of 0.98 g/(L h), 57% (w) and 67 g/L, respectively. Such novel process can be scaled up for significant cost reduction at the industrial level.
authors.forename: Z Y
authors.initials: ZY
authors.lastname: Zheng
authors.forename: Y
authors.initials: Y
authors.lastname: Jiang
authors.forename: X B
authors.initials: XB
authors.lastname: Zhan
authors.forename: L W
authors.initials: LW
authors.lastname: Ma
authors.forename: J R
authors.initials: JR
authors.lastname: Wu
authors.forename: L M
authors.initials: LM
authors.lastname: Zhang
authors.forename: C C
authors.initials: CC
authors.lastname: Lin
mesh_terms: D060054:Agrobacterium / Q000378:metabolism* / Q000648:ultrastructure; D000641:Ammonia / Q000378:metabolism; D061249:Batch Cell Culture Techniques; D019149:Bioreactors; D002244:Carbon / Q000378:metabolism*; D003470:Culture Media; D005285:Fermentation; D006863:Hydrogen-Ion Concentration; D009584:Nitrogen / Q000378:metabolism*; D010100:Oxygen / Q000378:metabolism; D011786:Quality Control; D047071:beta-Glucans / Q000378:metabolism*
chemical_list: D003470:Culture Media; D047071:beta-Glucans; C038459:curdlan; D002244:Carbon; D000641:Ammonia; D009584:Nitrogen; D010100:Oxygen