Biosynthesis of Silver and Gold Crystals Using Grapefruit Extract Long Chen, Jianli Wang, Hongfeng Wang, Zhaopeng Qi, Yuchuan Zheng, Junbo Wang, Le Pan, Guanru Chang and Yongmei Yang MATEC Web Conf., 67 (2016) 02016 Published online: 29 July 2016 DOI: 10.1051/matecconf/20166702016