Periplasmic/secreted acid trehalase that catalyzes hydrolysis of the disaccharide trehalose and required for growth on trehalose as carbon source (PubMed:26411890, PubMed:33146242). Growth on trehalose is not restricted to respiration (PubMed:26411890). alpha,alpha-trehalose + H2O = alpha-D-glucose + beta-D-glucose Homodimer. Abolishes growth in trehalose carbon source (PubMed:33146242). Normal growth in glucose carbon source (PubMed:33146242). Decreases virulence in a mouse infection model (PubMed:33146242). Belongs to the glycosyl hydrolase 65 family.