Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 12/17/2006
Publication Date: 12/17/2006
Citation: Manitchotpisit, P., Leathers, T.D., Prasongsuk, S., Eveleigh, D.E., Punnapayak, H. 2006. Color Variability, Pullulan Production, and Pullulan Degrading Enzyme Activities in Tropical Isolates of Aureobasidium Pullulans [abstract]. Abstracts of the 11th Biological Sciences Graduate Congress. p. 45.
Technical Abstract: Forty-six isolates from fifteen provinces in Thailand of the polymorphic fungus Aureobasidium pullulans were cultured. They were isolated from leaves, painted wall and wood surfaces. Each isolate was cultured in production medium (PM) containing sucrose and peptone as carbon and nitrogen sources, respectively, to compare the pullulan production level. They exhibited a range of color from cream, pale pink, burgundy red, light brown, and olivaceous green to black in PM. High pullulan yields were obtained from cream, pale pink, and dark olivaceous green cultures, while blastospores were the predominant cellular morphotypes. Previous studies demonstrated that the molecular weight of pullulan gradually decreased during cultivation period. Some of the isolates representing color variants were selected to analyze in order to study the relationship between color variability, pullulan production, and their related enzymes. Molecular analysis of the internal transcribed spacers (ITS) and the intergenic spacer (IGS) of nuclear ribosomal DNA were performed to determine the sequence similarity and the genetic diversity among these color variant isolates. Pullulan was collected periodically from PM cultures and then characterized for molecular weight, viscosity, and internal carbon bonding. During pullulan production, alpha-amylase and pullulanase activities were also assayed to determine their effect on the molecular weight of pullulan. Xylanase production was determined to compare the activities from these different sources, since color variants were previously reported to overproduce this enzyme.