Equity Properties and Development Co., Chicago, an affiliate of Zell/Merrill Lynch, has assumed responsibility for the management of the South Towne Mall, 10600 S. 110 West.

Zell/Merrill Lynch holds the notes on the loan for construction of the mall.Several months ago, Collier Management Co. filed a petition for reorganization under Chapter 11 of the Federal Bankruptcy Act. Equity officials and Allan Collier of Collier Management, are hopeful the bankruptcy judge will take the property out of bankruptcy and transfer ownership to Zell/Merrill Lynch.

South Towne operations will continue under the direction of Robert W. Robinson, who has been associated with the project since its inception and will continue his responsibilities for local management and leasing. Mall officials said the space is 80 percent occupied.

Groundbreaking for the 200,000 square-foot ZCMI, South Towne's anchor store, was in May 1985. Dedication ceremonies were July 31, 1986.