Eco-Sustainable Oilseed Biorefinery: Integrating Microwave with Magnetic Nanobiocatalysis

Abstract

We introduce a recyclable and efficient enzymatic process by integration of microwave (MW) pretreatment followed by magnetic nanobiocatalysis for the green and sustainable oilseed biorefinery. The magnetic nanobiocatalyst was prepared by immobilizing protease onto iron oxide magnetic nanoparticles and characterized using Fourier transform infrared spectroscopy, X-ray diffraction, field emission scanning electron microscopy, and transmission electron microscopy. The optimized MW pretreatment (450 W for 4 min) of fresh waste pomegranate seeds (WPS) followed by the magnetic nanobiocatalyst treatment (protease dosage of 30 U g–1 DW of WPS, pH 7, and 45 °C for 10 h) recovered 17.8% of oil slightly less than the hexane-derived oil (18.6%) together with the protein (15.9%) and dietary fiber-rich (97%) solid residue as coproducts. However, the magnetic nanobiocatalyst without MW pretreatment of WPS recovered only 13.1% of oil and 11% of protein even after 16 h of reaction. Excellent thermal stability and magnetic separation enabled the reuse of the magnetic nanobiocatalyst for at least four cycles without compromising the oil, protein, and dietary fiber recovery and protease activity. Additionally, the fatty acid composition, punicic acid and phenolic content, antioxidant activity of oil, and fiber composition and functional properties (oil/water holding capacity, glucose absorption capacity, and glucose dialysis retardation index) of the dietary fiber-rich solid residue from each cycle were also similar.

The Food–Materials Nexus: Next Generation Bioplastics and Advanced Materials from Agri‐Food Residues

“…[ 574 ] The obtained carbon was then successfully tested as electrode in a sodium battery, providing a constant charge–discharge cycle performance of 180 mAh g −1 at a C/2 rate and 100% columbic efficiency after 100 cycles. [ 574 ]…”

“…Another exciting development was the use of waste pomegranate peels to recover pectin (Section 3.2) and punicalagin (a rich source of phenolic compound), the leftovers of which were then carbonized via pyrolysis in presence of potassium hydroxide and heating, yielding hard carbon (nongraphitizable carbon). [ 574 ] The obtained carbon was then successfully tested as electrode in a sodium battery, providing a constant charge–discharge cycle performance of 180 mAh g −1 at a C/2 rate and 100% columbic efficiency after 100 cycles. [ 574 ]…”