Influence of Pyrimidine Supplementation on Pullulan Production by Aureobasidium pullulans ATCC 201253
Document Type
Thesis
Degree Name
Master of Science (MS)
Department
Chemistry
Date of Award
Summer 8-18-2025
Abstract
Pullulan is a maltotriose-containing glucan that has several commercial applications. This study explores the effect of pyrimidine supplementation on pullulan production by Aureobasidium pullulans ATCC 201253. The main objective of the study, which used fed-batch fermentation, explored whether uracil, uridine, cytosine or orotic acid supplementation enhanced fungal pullulan production when sucrose or glucose served as the carbon source. The fungal cultures were grown in a phosphate-buffered medium at pH 6.0 with aeration (200 rpm) for a period for 120 h at 28℃. The pullulan produced was precipitated by ethanol. The fungal cells were collected by centrifugation to determine cellular biomass. In sucrose-grown cells, cytosine supplementation following 48h produced the highest pullulan yield after 120 h at 28oC. In glucose-grown cells, uracil supplementation after 72 h produced the highest pullulan yield after 120 h at 28oC. In sucrose-grown cells, cytosine supplementation after 48 h produced the highest pullulan level which was the highest pullulan concentration produced during this work. Uridine phosphorylase and cytosine deaminase activities were detected in cell extracts independent of carbon source with the activities being higher in glucose-grown cells. The fungal cell utilization of uridine or cytosine is explained by the presence of these enzymes.
Advisor
Thomas West
Subject Categories
Biochemistry | Biochemistry, Biophysics, and Structural Biology | Life Sciences
Recommended Citation
Brefo, Emmanuel Osei, "Influence of Pyrimidine Supplementation on Pullulan Production by Aureobasidium pullulans ATCC 201253" (2025). Electronic Theses & Dissertations. 1310.
https://lair.etamu.edu/etd/1310
