Catalyzes the hydrolysis of alpha,alpha-trehalose into two molecules of D-glucose. alpha,alpha-trehalose + H2O = alpha-D-glucose + beta-D-glucose Shows an absolute requirement for inorganic phosphate for activity. The function of the phosphate may involve stabilizing the protein conformation and/or initiating protein aggregation. Unlike the threhalase ortholog in M.smegmatis, does not require Mg(2+) for activity. Glycan degradation; trehalose degradation; D-glucose from alpha,alpha-trehalose: step 1/1. Homomultimer. Belongs to the glycosyl hydrolase 15 family. Truncated N-terminus.