tProduction of fructooligosaccharide (FOS) through efficient cultivation of biotransformation process byfructosyltransferase (FTase) was evaluated by two new isolates, Aspergillus niger and Aspergillus flavusNFCCI 2364. The saccharide consumption revealed lag phase of A. niger in 10 h which were smaller extentthan A. flavus of 14 h. For the recycling of cell culture, the pellet cells were continuously reused after24 h of submerged fermentation by these microorganisms in which FTase activity remains stable in fourconsecutive cycles in A. niger and six cycles in A. flavus. When freshly prepared pellets were sonicated forefficient release of intracellular FTase, the best transformation reaction was performed at 20 W acousticpower giving conversion yield of FOS 61.43% (w/w) by A. niger and 70.44% (w/w) by A. flavus respectively.This study was shown that the two fungal isolates can serve as veritable source of intracellular FTase forindustrial production of FOS.