Catalyzes the phosphorylation of glycerol using ATP (PubMed:10759857, PubMed:11154065). Under anoxic conditions, when glycerol 3-phosphate accumulates in the glycosome, it catalyzes the reverse reaction, maintaining the ATP balance (PubMed:10759857, PubMed:11154065). Key enzyme for the survival of bloodstream forms under anoxic conditions (PubMed:11154065). ATP + glycerol = ADP + H(+) + sn-glycerol 3-phosphate Optimum pH is 8.0 (PubMed:10759857). Optimum pH is 8.5 for glycerol phosphorylation and 7.0 for ATP formation (PubMed:11154065). Polyol metabolism; glycerol degradation via glycerol kinase pathway; sn-glycerol 3-phosphate from glycerol: step 1/1. Belongs to the FGGY kinase family.