<i>Bacillus amyloliquefaciens</i>と<i>Rhizopus cohnii</i>の混合培養系を用いたグルコアミラーゼ生産 Glucoamylse Production in Submerged Co-Culture System of <i>Bacillus amyloliquefaciens</i> and <i>Rhizopus cohnii</i>

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Author(s)

    • 佐藤 貴裕 SATO Takahiro
    • 北九州市立大学大学院国際環境工学研究科 Graduate School of Environmental Engineering, The University of Kitakyushu
    • 森田 洋 MORITA Hiroshi
    • 北九州市立大学大学院国際環境工学研究科 Graduate School of Environmental Engineering, The University of Kitakyushu

Abstract

本論文では,原料に糊化米粉を使用し,糸状菌と細菌を混合培養することで液化工程を省略した液体培養法によるグルコアミラーゼ生産法の構築を目的とした.混合培養を行った結果,グルコアミラーゼ生産糸状菌<i>Rhizopus cohnii</i>の増殖に伴って培養液pHが低下し,α-アミラーゼ生産細菌である<i>Bacillus amyloliquefaciens</i>の増殖が困難であった.一方で<i>B. amyloliquefaciens</i>由来のプロテアーゼが<i>R. cohnii</i>の細胞壁溶解に関与することが明らかとなった.これらの問題に対して,酢酸アンモニウムの添加とそのタイミングが重要であることを見出した.とくに<i>B. amyloliquefacies</i>を24 h前培養した時点で<i>R. cohnii</i>及び3.84% (w/v)の酢酸アンモニウムを添加することで740 U/mlと高い活性を得ることに成功した.

We developed novel method for producing glucoamylase (GA) from gelatinized rice flour by co-culturing <i>Bacillus amyloliquefaciens</i> NBRC 14141 and <i>Rhizopus cohnii</i> P5. In liquid culture, the acidification of the growth medium due to the growth of <i>R. cohnii</i> prevented the growth of <i>B. amyloliquefaciens</i>; however, the <i>B. amyloliquefaciens</i> protease lysed <i>R. cohnii</i> cells, which decreased the production of GA. This antagonism was repressed by high concentrations of ammonium acetate in the growth medium. However, since low pH or high ammonium acetate concentrations inhibited the initial growth of <i>B. amyloliquefaciens</i>, it needed to be precultured without ammonium acetate. However, preculturing <i>B. amyloliquefaciens</i> for 48 h led to overproduction of protease, which inhibited the growth of <i>R. cohnii</i>. As a result, the maximum GA activity (740 U/ml) was obtained when <i>B. amyloliquefaciens</i> was precultured for 24 h followed by inoculation with <i>R. cohnii</i> in the presence of 3.84% (w/v) of ammonium acetate. These results indicated that GA can be produced at high levels from gelatinized rice flour by using a submerged co-culture system.

Journal

  • Japan Journal of Food Engineering

    Japan Journal of Food Engineering 12(2), 55-63, 2011

    Japan Society for Food Engineering

Codes

  • NII Article ID (NAID)
    130005078777
  • NII NACSIS-CAT ID (NCID)
    AA12076107
  • Text Lang
    ENG
  • Article Type
    Journal Article
  • Journal Type
    大学紀要
  • ISSN
    1345-7942
  • NDL Article ID
    11147665
  • NDL Source Classification
    ZP34(科学技術--食品工学・工業)
  • NDL Call No.
    Z74-C69
  • Data Source
    NDL  IR  J-STAGE 
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