Towards zero-waste biorefinery: extraction of bromelain and production of biosorbents from various components of Queen pineapples cultivated in Tripura, India

The Queen Pineapple of Tripura, India, renowned for its unique aroma and recently granted geographical indication, generates substantial waste (30–40% processing and on-farm waste). This study aims to utilize this waste as a sustainable raw material for bromelain recovery. Due to lack of data on Tripura based Queen Pineapple, the study was done using different parts of a Queen pineapple along with the Queen pineapple waste. To avoid use of organic solvent, the purification of crude Bromelain was done using ammonium sulfate followed by dialysis. For complete valorization, solid waste generated during purification of bromelain was converted into a biosorbent which was utilized to remove hexavalent chromium from aqueous solution in a batch biosorption system under varying experimental conditions. The activity of bromelain in different parts of a Queen pineapple was increased from 2–6 to 8–23 U/mg after purification. The pineapple waste contained 3 U/mg of Bromelain which was increased to 20 U/mg after purification. Addition of ammonium sulfate in the range of 20–60% led to highest purification factor. The pineapple waste-derived biosorbent effectively removed Cr (VI), with a Langmuir maximum capacity of 35 mg/g. The biosorption was fast, as 95% of its maximum capacity was removed within 60 min. Nonlinear models showed better predictability. This study establishes the viability of a circular bioeconomy for Queen Pineapple waste, showcasing its potential for bromelain recovery and solid waste conversion into a biosorbent for chromium removal. This dual approach contributes to economic and environmental sustainability.