Preparation method of LB medium

LB medium formula (per liter)

yeast extract5g,Tryptone10g,sodium chloride10g

NaOH adjusted the pH to 7.0121 ℃, and sterilized under high pressure for 20min.

LB solid medium

LB medium 1L

Agar powder15g

NaOH adjusted the pH to 7.0121 ℃, and sterilized under high pressure for 20min.

Sometimes antibiotics will be added to medium for bacterial growth, agar freezing point is 40 ℃, so the best temperature for adding antibiotics is 50-55 ℃.

Principle of LB medium: peptone and yeast extract powder provide nitrogen source, vitamin and growth factor; sodium chloride maintains balanced osmotic pressure; glucose provides carbon source; agar is the coagulant of medium.

Preparation of LB medium

Compounding per litre liquid medium for bacterial growth should add 10g tryptone,5g yeast extract and 10g NaCl to 950 ml deliquescent LB medium ionic water and shake the container until the solute dissolves. Adjust the PH to 7.0 with 5mol / LNaOH. Dilute to 1L with deionized water. Steam sterilization at 15psi for 20min.

1L of LB solid medium is the same as that of liquid medium. Add 15g agar powder. Before the temperature drops, add the antibiotic of LB solid medium, and pour the plate.