Escherichia coli for efficiently fermenting and producing L-alanine

Escherichia coli for efficiently fermenting and producing L-alanine

  • CN 104,774,790 B
  • Filed: 04/03/2015
  • Issued: 11/06/2020
  • Est. Priority Date: 04/03/2015
  • Status: Active Grant
First Claim
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1. A method for producing L-alanine by escherichia coli is characterized in that fermentation temperature is controlled in two stages, in the first stage, lower culture temperature is controlled, thalli are cultured under the aerobic condition of 28-35 ℃

  • to enable the thalli to grow rapidly without synthesizing L-alanine, then in the second stage, the culture temperature is increased, the thalli are cultured for a moment under the aerobic condition of 40-45 ℃

    , and then the stage of producing L-alanine by oxygen-limited fermentation is carried out;

    the Escherichia coli is preserved in the common microorganism center of China Committee for culture Collection of microorganisms at 16 days 3 months 2015, the preservation address is the microorganism research institute of China academy of sciences No. 3 of West Lu 1 of the North Zhongyang district in Beijing, the Escherichia coli (Escherichia coli) is classified and named, and the preservation number is CGMCC No. 10628;

    inoculating the activated escherichia coli into a fermentation tank with the liquid loading capacity of 60%, and performing two-stage fermentation, (1) aerobic stage culture;

    the initial air flux is 3L/min, the rotating speed of the stirring paddle is 200r/min, the dissolved oxygen concentration is set to be 100%, the air flux is adjusted to be 7L/min in the thallus growth process, and meanwhile, the stirring rotating speed is related to the DO value to control the dissolved oxygen concentration to be always more than 30%;

    controlling the pH value to be 7.0 and the fermentation temperature to be 28-35 ℃

    ;

    (2) and (3) oxygen-limited stage culture;

    when the thallus grows to the middle and late logarithmic phase, raising the temperature to 40-45 ℃ and

    continuing aerobic culture for 45 min;

    then entering an oxygen-limited fermentation acid-producing stage;

    adjusting the air flux to zero, controlling the rotating speed of a stirring paddle to be 100r/min, controlling the pH value to be 7.0, controlling the fermentation temperature to be 40-45 ℃

    , supplementing glucose with the concentration of 600g/L for three times, supplementing 200mL each time, so as to maintain the residual sugar concentration of the fermentation liquid to be higher than 10g/L in the fermentation process, and finishing the fermentation when all the supplemented glucose is consumed;

    per liter of fermentation medium contains;

    30g glucose, 15.11g Na2HPO4·

    12H2O,

    3g KH2PO4

    1g NH4Cl,

    0.5gNaCl,

    13.2g(NH4)2SO4And 1 per mill 1mol/L MgSO is supplemented4And 1 per mill of microelement mother liquor;

    the trace elements per liter contain;

    2.4g FeCl3·

    6H2O,

    0.3g CoCl2·

    6H2O,

    0.15g CuCl2·

    2H2O,

    0.3g ZnCl2

    0.3g Na2MO4·

    2H2O,

    0.075g H3BO3

    0.495g MnCl2·

    4H2O。

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