Why is it good to use Glycerol as carbon source to produce intermediates in pharmaceuticals?
First, glycerol is economically and environmentally interesting as a substrate. It is a side product of first generation biodiesel production, which has been increasing in the past years. So large amounts of glycerol are being accumulated, while we make little use of it. Therefore it has become a necessity to develop glycerol utilizing industries. Another consequence is that glycerol is now a cheap and abundant substrate.

The metabolism of glycerol is quite complex and has many end products that are of industrial relevance. For example, 1,3-propanediol and succinic acid have commercial applications and can be produced directly from glycerol by some microorganisms. So depending on the strain you use, you may not need heavy metabolic engineering.

Here is an article that might help you.