The purpose of this study was to establish the strategy to remove the cyanotoxin microcystin-LR (MC-LR) from aqueous solution with the use of biosorption strategy. Specifically, we focused on use of industrial waste biomass, Escherichia coli, to make efficient biosorbents for MC-LR through immobilization of the biomass with polysulfone (PS), coating the polysulfone-biomass composite with polyethylenimine (PEI), and decarboxylation of the PEI-coated composite to remove the inhibitory sites. The resulting sorbent is named in this study as decarboxylated PEI-coated polysulfone-biomass composite fiber (DC-PEI-PSBF). Various sorption experiments including isotherm, kinetics and pH effect on sorption capacity were conducted to evaluate the MC-LR adsorption performance of sorbents. As a result, the DC-PEI-PSBF could be suggested as a highly efficient sorbent able to be directly applied for MC-LR removal from aquatic natures.