Sulfur is needed for some amino acids (cysteine and methionine). It is also found in some vitamins (biotin, thiamine, lipoic acid). It is also needed for Coenzyme A.
Potassium is used by enzymes in protein synthesis. All living things require potassium.
Magnesium is needed to help ribosomes remain intact. Ribosomes are organelles that make protein.
Calcium protects cell walls and is necessary for heat stability in some microorganisms.
Sodium is required for growth of some marine (ocean) microorganisms.
Micronutrients
Micronutrients are required for life. However, they are only required in small amounts. There are many of these.
Iron is used by cytochromes. Cytochromes are involved in energy (ATP) synthesis. Iron is transported into siderophores. Siderphores bind iron and transport it into cells.
Some bacteria can grow without iron. In this case, manganese is used in place of iron.
Vitamins
Vitamins are chemicals that are required in very small quantities. Most often, vitamins are required for enzyme function. A list of vitamins is given below. Most microorganisms require only 1 or 2 of these. They can make the others that they need.
p-Aminobenzoic Acid Folic Acid
Biotin Cobalamin (B12)
Lipoic Acid Niacin
Pantothenic Acid Roboflavin
Thaimine (B1) B6 Vitamins
Vitamin K Group Hydroxamates