How to Make sodium lactate solution from solid sodium lactate?

Sodium lactate (the sodium salt of racemic or inactive lactic acid)

Sodium silicate is soluble in water so just add specific amount of this compound in specific amount of water, (as per requirement).

1. Pour water in a beaker. 2. Add ordinary table salt (sodium chloride). 3. Stir. The concentration of the solution will depend on how much salt you added.

yes, it selects for microbes that can grow in a sodium environment and ferment lactate

It comes from special plants. It is not 'laboratory' made but purified. Citation: "... certain plants and herbs which have bronchodilating properties. One such plant was 'Khella' (Ammi visnaga) which...