Combined effect of enzyme co-immobilized magnetic nanoparticles (MNPs) and ultrasound for effective extraction and purification of curcuminoids from Curcuma longa

The present work emphasizes co-immobilization of enzymes (glucoamylase and alpha-amylase) on magnetic nanoparticles (MNPs) using glutaraldehyde as a cross-linking agent for the pre-treatment of Curcuma longa powder. The co-immobilization process was optimized under various processing parameters to retain the maximum activity of both the enzymes in their co-immobilized system. The maximum activity recovery for both enzymes was obtained at MNPs to enzyme ratio of 1:4 and 60 mM glutaraldehyde concentration in 120 min of cross-linking time. Synthesized MNPs were characterized before and after co-immobilization using various methods. The synthesized enzymes@AMNPs have appeared spherical in shape with a mean particle size of 100 nm. The prepared biocatalyst also possesses super magnetic property with saturation magnetization (Ms) of 36.1 emu/g. Further, the combined effect of prepared biocatalyst and low power ultrasound was used to pre-treat the turmeric root powder for curcuminoids extraction. The synergistic effect enhances the extraction yield by 1.3-1.5 fold under the optimized solvent extraction process compared to the individual approach. The curcuminoids were separated using crystallization, which resulted in 54% (w/w) isolation with 91% purity of curcuminoids. Finally, the prepared biocatalyst showed excellent reusability up to 10 cycles with almost 50% activity and retained more than 95% activity when stored for up to 30 days.

Automated summary

The study emphasized co-immobilization of two enzymes on magnetic nanoparticles for the pre-treatment of Curcuma longa powder, retaining maximum enzyme activity. By optimizing the process parameters, the combined effect of the prepared biocatalyst and low power ultrasound improved the extraction yield of curcuminoids. The prepared biocatalyst showed excellent reusability for up to 10 cycles and retained over 95% activity after storage for 30 days.