Korean Chemical Engineering Research

  • 제55권3호
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  • Pages.363-368
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  • 2017
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  • 0304-128X(pISSN)
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  • 2233-9558(eISSN)
한국화학공학회 (The Korean Institute of Chemical Engineers)
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메탄올자화균 Methylobacterium extorquens AM1의 phaR 유전자 결실을 통한 poly 3-hydroxybutyrate (PHB) 생합성 억제

Inhibition of poly 3-hydroxybutyrate (PHB) synthesis by phaR deletion in Methylobacterium extorquens AM1

  • 김유진 (서강대학교 화공생명공학과) ;
  • 이광현 (서강대학교 생명과학과) ;
  • 김현수 (서강대학교 화공생명공학과) ;
  • 조숙형 (서강대학교 C1 Gas Refinery 사업단) ;
  • 이진원 (서강대학교 화공생명공학과)
  • Kim, Yujin (Department of Chemical and Biomolecular Engineering, Sogang University) ;
  • Lee, Kwanghyun (Department of Life Sciences, Sogang University) ;
  • Kim, Hyeonsoo (Department of Chemical and Biomolecular Engineering, Sogang University) ;
  • Cho, Sukhyeong (C1 Gas Refinery R&D Center, Sogang University) ;
  • Lee, Jinwon (Department of Chemical and Biomolecular Engineering, Sogang University)
  • 투고 : 2017.01.03
  • 심사 : 2017.02.13
  • 발행 : 2017.06.01
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초록

메탄올자화균이란 일탄소 화합물인 메탄올을 주탄소원 및 에너지원으로 이용할 수 있는 미생물을 말한다. Methylobacterium extorquens AM1은 serine cycle을 탄소대사경로로 이용하는 메탄올자화균 중에서도 가장 많이 연구가 진행된 균주이다. M. extorquens AM1의 poly 3-hydroxybutyrate (PHB) cycle은 EMCP (ethylmalonyl-CoA pathway), glyoxylate regeneration cycle, TCA cycle과 연결되어 있으며 EMCP 유래 유기산 또는 TCA 유기산을 생산하기 위해서는 PHB cycle로 흐르는 carbon flux의 차단이 필요하다. 이를 위해서 PHB 합성과 acetyl-CoA flux의 조절유전자로 알려져 있는 PhaR 유전자를 markerless gene deletion 방법을 이용해서 M. extorquens AM1에서 knockout했다. 결과적으로, knockout 균주인 ${\Delta}phaR$에서 야생종 대비 확연히 PHB granule이 줄어든 것이 확인되었다. Lag phase가 약 12 h 늦어졌지만, ${\Delta}phaR$은 야생종과 비슷한 세포성장과 메탄올소비 경향을 보임을 확인하였다.

Methylotrophy is able to use reduced one-carbon compound, such as methanol and methylamine, as a sole carbon source. Methylobacterium extorquens AM1 is the most extensively studied methylotroph utilizing serine-isocitrate lyase cycle. Because the Poly 3-hydroxybutyrate (PHB) synthesis pathway in M. extorquens AM1 is likely to interlink with EMCP (ethylmalonyl-CoA pathway), glyoxylate, and TCA cycles, regulation of PHB production is needed to produce EMCP-derived acid or TCA acids. To adjust carbon flux to PHB production, PhaR, which seems to have function of regulator of PHB synthesis and acetyl-CoA flux, was knocked out in M. extorquens AM1 by using markerless gene deletion methods. As a result, PHB granules were remarkably reduced in the knockout strain ${\Delta}phaR$ compared to parental strain. Although lag phase was extended for 12h, ${\Delta}phaR$ showed similar cell growth and methanol consumption rate compared to wild type.

키워드

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