Task-specific ionic liquid for the depolymerisation of starch-based industrial waste into high reducing sugars

•Depolymerisation of starch-based industrial waste into reducing sugars.•Valorisation of industrial waste into high value-added chemicals.•Comparison of two ionic liquids for the dissolution and hydrolysis of starch.•Evaluation on the use of microwave and ultrasound technologies in association with ionic liquids.

Development of a simple route for the catalytic conversion of starch-based industrial waste (potato peels) and potato starch into reducing sugars was investigated in two ionic liquids for comparison – 1-allyl-3-methylimidazolium chloride [AMIM]Cl and 1-(4-sulfobutyl)-3-methylimidazolium chloride [SBMIM]Cl. Over a two hour period, a 20 wt% solution containing up to 43% and 98% of reducing sugars at low temperature in aqueous [SBMIM]Cl was achieved for the starch-based waste and the potato starch, respectively. In addition, the use of microwave and low frequency ultrasound to perform the depolymerisation of the raw starch-based material was explored and compared with conventional heating processes.

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