1. Zuckerberg Institute for Water Research, Unit of Environmental Engineering, and Department of Biotechnology Engineering, Ben-Gurion University of the Negev, P.O. Box 635, Beer-Sheva 84105, Israel, and European Synchrotron Radiation Facility, ID10B, 6 Rue Jules Horowitz, BP-220, 38043 Grenoble CEDEX, France