This experiment searches for indications of the metabolic pathways, displayed by the trace metal contents, of exceptionally well-preserved 2 Ga old filamentous microfossils from Gabon. Trace metals will be quantified from nano-XRF images of both longitudinal and transverse FIB sections of the filaments (ES-1167 6 shifts @ ID16B in April 2022). Our present request is a new XANES measurement of 6 shifts on ID21 at Sulphur K-edge (E≈2.5 keV) to complete the important step of demonstrating that Ni is linked to organic compounds. This study will form the basis for comparison with the oldest microfossils that utilize methane metabolism and will evaluate novel metabolism emergence, associated with the Great Oxygenation Event (GOE).