Kane’s Donuts faces new lawsuit from business partner

Kane’s Donuts, already mired in a lawsuit among family members, is now facing another court challenge: an allegation from a business partner that it hasn’t adhered to an arbitration ruling from January.A limited liability corporation named John Dough LLC, which owns 30% of Kane’s downtown Boston store at 90 Oliver St., argues in the lawsuit that Kane’s, which owns the other 70%, breached an agreement. The breach involves Kane's Route 1 store in Saugus.“A variety of