title: The mechanism of improved pullulan production by nitrogen limitation in batch culture of Aureobasidium pullulans.
abstract: Batch culture of Aureobasidium pullulans CCTCC M 2012259 for pullulan production at different concentrations of ammonium sulfate and yeast extract was investigated. Increased pullulan production was obtained under nitrogen-limiting conditions, as compared to that without nitrogen limitation. The mechanism of nitrogen limitation favoring to pullulan overproduction was revealed by determining the activity as well as gene expression of key enzymes, and energy supply for pullulan biosynthesis. Results indicated that nitrogen limitation increased the activities of α-phosphoglucose mutase and glucosyltransferase, up-regulated the transcriptional levels of pgm1 and fks genes, and supplied more ATP intracellularly, which were propitious to further pullulan biosynthesis. The economic analysis of batch pullulan production indicated that nitrogen limitation could reduce more than one third of the cost of raw materials when glucose was supplemented to a total concentration of 70 g/L. This study also helps to understand the mechanism of other polysaccharide overproduction by nitrogen limitation.
authors.affiliation: College of Food Science and Technology, Nanjing Agricultural University, Nanjing 210095, PR China; School of Biology and Basic Medical Sciences, Soochow University, Suzhou 215123, PR China.
authors.forename: Dahui
authors.initials: D
authors.lastname: Wang
authors.affiliation: School of Biology and Basic Medical Sciences, Soochow University, Suzhou 215123, PR China.
authors.forename: Feifei
authors.initials: F
authors.lastname: Chen
authors.affiliation: School of Biology and Basic Medical Sciences, Soochow University, Suzhou 215123, PR China.
authors.forename: Gongyuan
authors.initials: G
authors.lastname: Wei
authors.affiliation: State Key Laboratory of Materials-Oriented Chemical Engineering, Nanjing University of Technology, Nanjing 210009, PR China.
authors.forename: Min
authors.initials: M
authors.lastname: Jiang
authors.affiliation: College of Food Science and Technology, Nanjing Agricultural University, Nanjing 210095, PR China. Electronic address: dongms@njau.edu.cn.
authors.forename: Mingsheng
authors.initials: M
authors.lastname: Dong
mesh_terms: D000255:Adenosine Triphosphate / Q000378:metabolism; D001203:Ascomycota / Q000235:genetics / Q000378:metabolism*; D005800:Genes, Fungal; D005936:Glucans / Q000096:biosynthesis* / Q000235:genetics; D007218:Industrial Microbiology / Q000379:methods*; D009584:Nitrogen / Q000172:deficiency* / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism
chemical_list: D005936:Glucans; D012333:RNA, Messenger; D000255:Adenosine Triphosphate; C009109:pullulan; D009584:Nitrogen
keywords: ATP supply; Adenosine triphosphate (PubChem CID: 5957); Ammonium sulfate (PubChem CID: 6097028); Aureobasidium pullulans; Enzyme activity; Gene expression; Glucose (PubChem CID: 5793); Nitrogen limitation; Pullulan; Pullulan (PubChem CID: 3085039)