Identification of potential cell wall component that allows Taka-amylase A adsorption in submerged cultures of Aspergillus oryzae

Hiroki Sato, Yoshiyuki Toyoshima, Takahiro Shintani, Katsuya Gomi

    Research output: Contribution to journalArticlepeer-review

    22 Citations (Scopus)

    Abstract

    We observed that α-amylase (Taka-amylase A; TAA) activity in the culture broth disappeared in the later stage of submerged cultivation of Aspergillus oryzae. This disappearance was caused by adsorption of TAA onto the cell wall of A. oryzae and not due to protein degradation by extracellular proteolytic enzymes. To determine the cell wall component(s) that allows TAA adsorption efficiently, the cell wall was fractionated by stepwise alkali treatment and enzymatic digestion. Consequently, alkali-insoluble cell wall fractions exhibited high levels of TAA adsorption. In addition, this adsorption capacity was significantly enhanced by treatment of the alkali-insoluble fraction with β-glucanase, which resulted in the concomitant increase in the amount of chitin in the resulting fraction. In contrast, the adsorption capacity was diminished by treating the cell wall fraction with chitinase. These results suggest that the major component that allows TAA adsorption is chitin. However, both the mycelium and the cell wall demonstrated the inability to allow TAA adsorption in the early stage of cultivation, despite chitin content in the cell wall being identical in both early and late stages of cultivation. These results suggest the existence of unidentified factor(s) that could prevent the adsorption of TAA onto the cell wall. Such factor(s) is most likely removed or diminished from the cell wall following longer cultivation periods.

    Original languageEnglish
    Pages (from-to)961-969
    Number of pages9
    JournalApplied Microbiology and Biotechnology
    Volume92
    Issue number5
    DOIs
    Publication statusPublished - 2011 Dec

    Keywords

    • Aspergillus oryzae
    • Cell wall
    • Chitin
    • Protein production
    • Submerged culture
    • α-Amylase

    ASJC Scopus subject areas

    • Biotechnology
    • Applied Microbiology and Biotechnology

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