Nanobiocatalyst based on covalent immobilization of proteases onto functionalized nanocellulose for efficient production of sunflower meal protein hydrolysates

Abstract

This study aimed to engineer bio-based and environmentally friendly nanobiocatalyst systems using commercially available protease preparations, Alcalase® 2.4L (Alcalase) and Flavourzyme® (Flavourzyme), along with functionalized cellulose nanocrystals (CNC). The study highlights the advantageous properties of the obtained glutaraldehyde-activated amino-modified CNC support (GA-amino-CNC), characterized as nanorods with dimensions ranging between 100-800 nm in length and 40-60 nm in width, particularly for protease immobilization. Maximum specific activity of immobilized Alcalase (15 IU/mg of proteins) was achieved at an initial enzyme concentration of 52 mg/g of support after 3 hours, with 80% of covalently attached enzyme molecules. In the case of Flavourzyme, maximum exo-hydrolytic activity of 21 L-pNAU/g of support was observed after 20 min, while a higher yield of covalently bound enzyme molecules (53%) detected after 1 hour. The covalently bound proteases on glutaraldehyde-activated amino-modified cellulose nanocrystals were evaluated for their efficacy in producing high-quality sunflower-based protein hydrolysates suitable for food and feed applications. Sequential hydrolysis of sunflower meal protein isolate (SMPI) using the developed nanobiocatalysts yielded a maximum hydrolysis degree of 20%. In addition, more than 80% of the initial activity of nanobiocatalysts were retained after 3 reuses, suggesting that these protease nanobiocatalysts have potential application in production of SMP hydrolysates.