Whenever I am preparing LB media containing Zinc sulphate at greater than 100 ppm concentration, it is getting precipitated. What could be done to avoid this problem as I need Zinc Sulphate at greater than 100 ppm.
Well, I am not sure if it is zinc sulfate that is precipitating out or something else. Zinc sulfate (hepta hydrate) is soluble in water at 100 mg/mL whereas your desired concentration is just 100 mg/L. What is the order of addition? Are you adding solid zinc sulfate or the stock solution (in water) to the LB medium? Or are you dissolving zinc sulfate first in water and then adding NaCl, tryptone, and yeast extract?
Thanks for reply sir. Actually I have used both stock solution and solid zinc sulphate and in both cases precipitation is occurring. I am using HiMedia's ready made LB. Sir, I am not sure whether it is right to say it as precipitation, whenever I am adding zinc sulphate in higher concentration (> 100 ppm), whole media is becoming very turbid so after the inoculation of bacterial culture it is very difficult to observe growth. Also there is formation of white precipitate in both control ( LB + znso4) as well as inoculated media (LB+znso4+bacteria) after 1 day incubation of both at 370C at 120 rpm.
OK Shraddha, have you ever tried to dissolve ZnSO4 in the water first? What happens? Does it get dissolved completely? What if you add the powdered medium components now?
Sir I have tried dissolving ZnSO4 in the water and then adding into the medium but it got precipitated. It got dissolved completely in water. As you have asked I haven't tried adding powdered medium components. I think it should be a good solution and I'll try that too. Thank you
I am currently trapped in a similar problem. I have different situations that when the metal is zinc, the final solution looks milky; when the metal is lead, white precipitaion occurred at the bottom of test tubes. I wonder if you have solved this problem and I will be appreciated if you are willing to share your experience.
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