LB Nutrient Agar is a nutritionally rich medium originally developed for growth and maintenance of E. coli strains. LB Nutrient Agar is the most widely used medium for the growth of bacteria. The composition of 1 liter of LB Nutrient Agar contains：10.0 g tryptone, 5.0 g yeast, 10.0 g sodium chloride, and 15.0 g agar^[1].