Insulin-dependent diabetics rely on insulin to uptake glucose from their bloodstream. Insulin is a human protein, not produced by microorganisms.

However, the insulin used by diabetics is often produced using genetically modified bacteria (like E. coli) or yeast. These organisms have been engineered to contain the human insulin gene and therefore produce human insulin, which is then purified and used for treatment.

So, while the microorganisms themselves don't produce the protein, they are essential in the biotechnological production of insulin for diabetic patients.