This paper introduces biosorption technology using a metal recovery material made from cyanobacteria as an environmentally friendly. This metal recovery material is characterized by its ability to selectively recover precious metals dissolved in water, with a recovery rate of over 95%. In the case of gold recovery from hydrogen tetrachloroaurate (III) tetrahydrate solution, the reaction proceeds at a rate of less than a few minute, and the high recovery performance at low pH level is demonstrated. The main component of the metal recovery material is a photosynthetic dye, pheophytin a, which was found to be an important molecule for the recovery of precious metals.
