Enhancement of ginsenoside Rg1 in Panax ginseng hairy root by overexpressing the α-l-rhamnosidase gene from Bifidobacterium breve - Ru Zhang; Bian-Ling Zhang; Gu-Cai Li; Tao Xie; Teng Hu; Zhi-Yong Luo (Biotechnology Letters, 2015)