Mechanistic understanding and performance enhancement of biosorption of reactive dyestuffs by the waste biomass generated from amino acid fermentation process

Biosorption has been demonstrated as a useful alternative to conventional treatment systems for the removal of dyes from dilute aqueous solution. This study dealt with a renewable, low cost biosorbent derived from the waste biomass of Corynebacterium glutamicum which are generated from full-scale amino acid fermentation industry. The biosorbent has been proved to have a higher (or comparable) dye uptake capacity than conventional sorbents, such as activated carbons and ion-exchange resins. This study focused on the underlying mechanisms of dye binding to the biosorbent. The binding sites were identified to be primary amine groups present in the biomass. Chemical modification of the biomass, FT-IR and potentiometric titration studies revealed that carboxyl and phosphate groups played a role in repulsion of dye molecules, inhibiting the dye binding to the biosorbent. With the help of elucidated biosorption mechanisms, the performance of biosorbent for practical application could be enhanced by removal of the inhibitory carboxyl groups.