Acacia Gum or Arabic Gum is a hardened sap often sold as a dietary supplement in powdered form. It is fed to gliders as a treat or part of a captive diet in some cases by the addition of liquid to the powder thus making a gummy paste. In the wild sugar gliders consume wattle from the acacia genus. It is not clear if the species used in the production of Arabic Gum; Acacia senegal and Acacia seyal; are species sugar gliders normally eat from.
Sources

http://www.senrm.sa.gov.au/LinkClick.aspx?fileticket=geabJ__nPNw%3D&tabid=400&mid=1297
http://en.wikipedia.org/wiki/Gum_arabic
VGV Diet