Title page for ETD etd-01102001-121200

Type of Document Master's Thesis
Author Affleck, Richard Peter
Author's Email Address r_affleck@hotmail.com
URN etd-01102001-121200
Title Recovery of Xylitol from Fermentation of Model Hemicellulose Hydrolysates Using Membrane Technology
Degree Master of Science
Department Biological Systems Engineering
Advisory Committee
Advisor Name Title
Agblevor, Foster Aryi Committee Chair
Chen, Jiann-Shin Committee Member
Cundiff, John S. Committee Member
Glasser, Wolfgang G. Committee Member
  • xylitol
  • reverse osmosis
  • ultrafiltration
  • nanofiltration
  • fermentation
Date of Defense 2000-12-12
Availability unrestricted
Xylitol can be produced from xylose or hemicellulose hydrolysates by either chemical reduction or microbial fermentation. Current technology for commercial production is based on chemical reduction of xylose or hemicellulose, and xylitol is separated and purified by chromatographic methods. The resultant product is very expensive because of the extensive purification procedures.

Microbial production of xylitol is being researched as an alternative method for xylitol production. Apart from the chromatographic separation method and activated carbon treatment, no other separation method has been proposed for the separation of xylitol from the fermentation broth.

Membrane separation was proposed as an alternative method for the recovery of xylitol from the fermentation broth because it has the potential for energy savings and higher purity. A membrane separation unit was designed, constructed, tested, and successfully used to separate xylitol from the fermentation broth. Eleven membranes were investigated for xylitol separation from the fermentation broth. A 10,000 nominal molecular weight cutoff (MWCO) polysulfone membrane was found to be the most effective for the separation and recovery of xylitol. The membrane allowed 82.2 to 90.3% of xylitol in the fermentation broth to pass through while retaining 49.2 to 53.6% of the Lowry’s method positive material (such as oligopeptides and peptides). Permeate from the 10,000 MWCO membrane was collected and crystallized. Crystals were analyzed by HPLC for xylitol and impurities and determined to have purity up to 90.3%.

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