ATP bio-sensor Economics is a vital aspect of any system, be it the world, a country, a person or even a microbe. Fungi are being used extensively by the biotechnology industry to produce useful compounds like drugs, organic acids, enzymes, fuels, etc. Thus efficient use of cellular resources is of prime importance in these industrial workhorses. Now the energy currency of any cell is Adenosine tri-phosphate (ATP) molecule and visualizing the dynamics of ATP levels in living cells has been a challenge. To this end we aim to produce a Fluorescence resonance energy transfer (FRET) based sensor for live cell ATP measurements in Aspergillus niger. With this we hope to measure ATP levels between compartments in growing Aspergillus niger during major metabolic shifts to understand the energy management processes in the cell.