A triparental conjugation technique (using pRL10630 plasmid) was used in creation and characterization of three transposon-induced mutants of Anabaena PCC7120 which are capable of extracellular ammonia liberation in the absence and/or presence of a glutamate analogue (MSX). Results suggest that such mutants can potentially serve as suitable biofertilizer to support crops without addition of the glutamate analogue.