The aim of the proposed study is to investigate the capacity of the commercially and environmentally important microalga Chlorella sorokiniana to synthetize metal clusters using an excess of copper. This is the only alga that has been previously documented to synthesize organized metal clusters with multiple redox states, indicating a tremendous biotechnological potential for catalytic/redox applications. Our preliminary data show that Chlorella sorokiniana accumulates copper in Cu2+ and Cu1+ forms in sufficient amounts for X-ray absorption fine structure (XAFS) spectroscopy to be performed. Even more, analyses show that the organization of Cu deposits may be altered by changing extracellular pH, i.e. the process of synthesis may be (at least partially) controlled. In order to elucidate the structure of Cu accumulations, high energy resolution fluorescence detected X-ray absorption near edge structure (XANES/HERFD)) and EXAFS should be applied as methods that can provide this type of i