Periplasmic acid trehalase that catalyzes hydrolysis of the disaccharide trehalose and required for growth on trehalose as carbon source (PubMed:15128531). Growth on trehalose is strictly respiratory (PubMed:15128531). alpha,alpha-trehalose + H2O = alpha-D-glucose + beta-D-glucose May localize to the periplasm either as a membrane-bound or as a free protein (PubMed:15128531). Vacuolar localization appears to be associated with its degradation (By similarity). Glycosylated. Severely decreases growth on trehalose carbon source, simultaneous disruption of AGT1 or NTH1 abolishes growth. Belongs to the glycosyl hydrolase 65 family.