• Title/Summary/Keyword: engineered PCC

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Morphological Analysis of Engineered PCC by Gas-Liquid Mixing Conditions (기체-액체 혼합조건에 따른 Engineered PCC의 형태학적 분석)

  • Lee, Tai-Ju;Seo, Jin-Ho;Kim, Hyoung-Jin
    • Journal of Korea Technical Association of The Pulp and Paper Industry
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    • v.43 no.3
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    • pp.113-120
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    • 2011
  • Precipitated calcium carbonate(PCC), particularly calcite crystal, is extensively used as a pigment, filler or extender in various industries such as paper, paint, textile, detergents, adhesives, rubber and plastics, food, cosmetics, and biomaterials. PCC is conventionally produced through the gas-liquid carbonation process, which consists on bubbling gaseous $CO_2$ through a concentrated calcium hydroxide slurry. This study is aimed to find some factors for controlling the morphology of engineered PCC in lab-scaled mixing batch. The experimental designs were based on temperature variables, $Ca(OH)_2$ concentration, $CO_2$ flow rate, and electrical conductivity. The model of engineered PCC morphology was finally controlled by adjustment of electrical conductivity(6.0~7.0 mS/cm) and $Ca(OH)_2$ concentration(10 g/L). Orthorhombic calcite crystals were mostly created at high concentration and electrical conductivity conditions because the increased ratio of $Ca^{2+}$ and $CO{_3}^{2-}$ ions affects the growth rate of orthorhombic faces. Excess calcium spices were contributed to the growth of faces in calcium carbonate crystal, and the non-stoichiometric reaction was occurred between $Ca^{2+}$ and $CO{_3}^{2-}$ ions during carbonation process.

Evaluation of Photosynthetic Squalene Production of Engineered Cyanobacteria Using the Chemical Inducer-Free Expression System (무-유도인자 단백질 발현 시스템을 이용한 재조합 시아노박테리아의 광합성 스쿠알렌 생산 평가)

  • Choi, Sun Young;Woo, Han Min
    • Microbiology and Biotechnology Letters
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    • v.49 no.3
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    • pp.298-304
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    • 2021
  • Photosynthetic conversion through cyanobacteria and microalgae is an increasingly serious concern in the global warming crisis. Many value-added substances are produced through strain improvement, and much research and development is being conducted to determine its potential as an actual industrial strain. Economic barriers throughout processing production can be overcome to produce value-added chemicals by microalgal strains. In this study, we engineered cyanobacteria strains for the photosynthetic production of squalene and confirmed the continuous cultivation of CO2 and light conditions. The free-inducer system of gene expression was developed at the cyanobacterial strains. Then, the squalene production level and growth of the recombinant cyanobacteria were analyzed and discussed. For bio solar-cell factories, the ability to regulate genes based on the free-inducer gene expression system promotes metabolic engineering research and construction to produce value-added chemicals.