Pb(II)-inducible proviolacein biosynthesis enables a dual-color biosensor toward environmental lead oleh De-long Zhu, Yan Guo, Bing-chan Ma, Yong-qin Lin, Hai-jun Wang, Chao-xian Gao, Ming-qi Liu, Nai-xing Zhang, Hao Luo, Chang-ye Hui, Chang-ye Hui