Need of separate PAN for business of a Proprietor already having Personal PAN ?

Whether a Person (being an Individual Proprietor of a Business with Shop Act License) already having PAN (as an Individual) need to obtain a separate PAN for such Proprietary Business?
If yes, is there any specific provision or case law for the same?
If yes, then which two ITRs (one as an Individual with Business income and other for the Proprietary Business) need to be filed ?
Thanks !!