title: Evaluation of kojic acid production in a repeated-batch PCS biofilm reactor.
abstract: In this study, kojic acid, a secondary metabolite as an industrially important compound, was produced by Aspergillus oryzae (A. oryzae), which was immobilized in plastic composite support (PCS) bioreactor. Nitrogen deficient medium was applied to increase the production of KA in PCS-immobilized bioreactor. The efficiency of immobilized culture for kojic acid (KA) production and the effect of morphology of A. oryzae on KA production were evaluated. After three cycles of cultivation, 83.47 g/L of KA was produced in PCS bioreactor in nitrogen deficient medium with productivity of 3.09 g/L/d, which is higher than free suspension culture in batch fermentation. The morphology of A. oryzae mycelium changed under nitrogen starvation. Feather-like mycelium was observed with increasing KA production. RNA expression (kojA and kojT) results indicated that the nitrogen deficient environment had strong influence on KA production on the transcriptional level. PCS immobilized fermentation system, which allowed a repeated-batch fermentation with higher production and productivity, is a potential tool in industrial production of KA.
authors.affiliation: Division of Urology, Department of Surgery, Taoyuan General Hospital, Ministry of Health and Welfare 1492, Chung-Shan Road, Taoyuan District, Taoyuan 330, Taiwan.
authors.forename: Jui-Ming
authors.initials: JM
authors.lastname: Liu
authors.affiliation: Graduate Institute of Food Science and Technology, National Taiwan University, Taipei, Taiwan No.1, Sec. 4, Roosevelt Road, Taipei, Taiwan.
authors.forename: Ting-Chu
authors.initials: TC
authors.lastname: Yu
authors.affiliation: Institute of Biotechnology, National Taiwan University, Taipei, Taiwan No. 81, Chang-Xing St., Taipei 106, Taiwan.
authors.forename: Shin-Ping
authors.initials: SP
authors.lastname: Lin
authors.affiliation: Biobank Management Center of Tri-Service General Hospital, National Defense Medical Center, Taipei, Taiwan; Department of Pathology and Graduate Institute of Pathology and Parasitology, Tri-Service General Hospital, National Defense Medical Center, Taipei, Taiwan No. 161, Sec. 6, Minquan E. Road, Neihu District, Taipei 114, Taiwan.
authors.forename: Ren-Jun
authors.initials: RJ
authors.lastname: Hsu
authors.affiliation: Institute of Biotechnology, National Taiwan University, Taipei, Taiwan No. 81, Chang-Xing St., Taipei 106, Taiwan.
authors.forename: Kai-Di
authors.initials: KD
authors.lastname: Hsu
authors.affiliation: Graduate Institute of Food Science and Technology, National Taiwan University, Taipei, Taiwan No.1, Sec. 4, Roosevelt Road, Taipei, Taiwan; Institute of Biotechnology, National Taiwan University, Taipei, Taiwan No. 81, Chang-Xing St., Taipei 106, Taiwan. Electronic address: kccheng@ntu.edu.tw.
authors.forename: Kuan-Chen
authors.initials: KC
authors.lastname: Cheng
mesh_terms: D001236:Aspergillus oryzae / Q000254:growth & development / Q000378:metabolism*; D061249:Batch Cell Culture Techniques / Q000379:methods*; D018441:Biofilms; D018533:Biomass; D019149:Bioreactors / Q000382:microbiology*; D018914:Cells, Immobilized; D003470:Culture Media; D005285:Fermentation; D006863:Hydrogen-Ion Concentration; D007218:Industrial Microbiology / Q000379:methods; D009584:Nitrogen / Q000172:deficiency / Q000378:metabolism; D010969:Plastics / Q000737:chemistry*; D016133:Polymerase Chain Reaction; D011753:Pyrones / Q000378:metabolism*
chemical_list: D003470:Culture Media; D010969:Plastics; D011753:Pyrones; C011890:kojic acid; D009584:Nitrogen
keywords: Aspergillus oryzae; Biofilm reactor; Kojic acid; Plastic composite support; Repeated batch