The mayor has been a central figure in the drawn-out sale process of the club, with U.S. group Di Benedetto given an exclusive 30-day window to discuss a purchase of Roma.
Ranieri quit on Sunday following fan protests and after eighth-placed Roma went down 4-3 at Genoa having been 3-0 up. They also lost 3-2 at home in a Champions League first leg to last 16 debutants Shakhtar Donetsk last week.
"I think we are talking about a consortium made up of experts who won't be scared," Alemanno told reporters.
Roma bosses were holding a meeting with Ranieri and the squad on Monday to decide who to appoint as coach with youth team boss Vincenzo Montella the fans' favourite and Chelsea coach Carlo Ancelotti long linked in the media.
Italy coach Cesare Prandelli has praised Ranieri for showing "responsibility and dignity" by resigning.