Can you replace glucose with glycerol in cell media?
In most cases, it's not a good idea to replace glucose with glycerol in animal cell media. Animals do possess the ability to metabolize glycerol, via a pathway starting with the enzyme glycerol kinase. However, glycerol kinase is only expressed in certain cell types, such as liver cells and kidney cells.

References:

http://www.brenda-enzymes.org/enzyme.php?ecno=2.7.1.30
http://www.ncbi.nlm.nih.gov/books/NBK22591/