Hutner's trace elements

    Hutner et al. (1950) Proc. Am. Philos. Soc. 94, 152-170

    This mixture is used both in TAP and in the Sueoka high salt medium.

    For a detailed analysis of how well this trace elements solution meets the nutritional requirements of C. reinhardtii, see Merchant et al. (2006) Biochim. Biophys. Acta 1763, 578-594.

     

    For 1 liter final mix, dissolve each compound in the volume of water indicated.

    The EDTA should be dissolved in boiling water, and the FeSO4 should be prepared last to avoid oxidation.

    compoundamountwater
    EDTA disodium salt50 g250 ml
    ZnSO4 . 7 H2O22 g 100 ml
    H3BO311.4 g200 ml
    MnCl2 . 4 H2O5.06 g50 ml
    CoCl2. 6 H2O1.61 g50 ml
    CuSO4 . 5 H2O 1.57 g50 ml
    (NH4)6Mo7O24. 4 H2O 1.10 g50 ml
    FeSO4. 7 H2O 4.99 g50 ml

    Mix all solutions except EDTA. Bring to boil, then add EDTA solution. The mixture should turn green. When everything is dissolved, cool to 70 degrees C. Keeping temperature at 70, add 85 ml hot 20% KOH solution (20 grams / 100 ml final volume). Do NOT use NaOH to adjust the pH.

    Bring the final solution to 1 liter total volume. It should be clear green initially. Stopper the flask with a cotton plug and let it stand for 1-2 weeks, shaking it once a day. The solution should eventually turn purple and leave a rust-brown precipitate, which can be removed by filtering through two layers of Whatman#1 filter paper, repeating the filtration if necessary until the solution is clear. Store refrigerated or frozen convenient aliquots. Some people shorten the time for formation of the precipiate by bubbling the solution with filtered air.

    If no precipitate forms, the solution is still usable. However, you might want to check the pH in this case and adjust it to around 7.0 using either KOH or HCl as needed.

    To prepare sulfur-free trace elements for hydrogen generation, the sulfate salts can be replaced with equimolar chloride salts (ZnCl2 10.0 g; CuCl2 . 2 H2O 1.00 g; FeCl2 . 4 H2O, 3.60 g). .

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