Enzymatic Hydrolysis of Bacterial Cellulose for the Production of Nanocrystals for the Food Packaging Industry

Abstract

Bacterial cellulose nanocrystals (BCNCs) obtained by enzymatic hydrolysis have been loaded in pullulan biopolymer for use as nanoparticles in the generation of high-oxygen barrier coatings intended for food packaging applications. Bacterial cellulose (BC) produced by Komagataeibacter sucrofermentans was hydrolyzed by two different enzymatic treatments, i.e., using endo-1,4-β-glucanases (EGs) from Thermobifida halotolerans and cellulase from Trichoderma reesei. The hydrolytic activity was compared by means of turbidity experiments over a period of 145 h, whereas BCNCs in their final state were compared, in terms of size and morphology, by atomic force microscopy (AFM) and dynamic light scattering (DLS). Though both treatments led to particles of similar size, a greater amount of nano-sized particles (≈250 nm) were observed in the system that also included cellulase enzymes. Unexpectedly, transmission electron microscopy (TEM) revealed that cellulose nanoparticles were round-shaped and made of 4–5 short (150–180 nm) piled whiskers. Pullulan/BCNCs nanocomposite coatings allowed an increase in the overall oxygen barrier performance, of more than two and one orders of magnitude (≈0.7 mL·m−2·24 h−1), of pure polyethylene terephthalate (PET) (≈120 mL·m−2·24 h−1) as well as pullulan/coated PET (≈6 mL·m−2·24 h−1), with no significant difference between treatments (hydrolysis mediated by EGs or with the addition of cellulase). BCNCs obtained by enzymatic hydrolysis have the potential to generate high oxygen barrier coatings for the food packaging industry.

Acid-derived bacterial cellulose nanocrystals as organic filler for the generation of high-oxygen barrier bio-nanocomposite coatings

“…These results are supported by previous scientic research, [46][47][48] and ascribed to water molecules competing for the -OH groups displaced along both the biopolymer and ller backbones and participating in intermolecular hydrogen bonding. 30,33 Overall, our data are in line with the results obtained in other works (Table 2), demonstrating the potential of biopolymer coatings to improve the oxygen barrier properties of PET without jeopardizing its intrinsic optical properties.…”

“…28,29 Conversely, our recent work involved a pullulan-based coating formulation reinforced with enzymatically derived BCNCs as organic nanollers, applied to bare polyethylene terephthalate (PET) substrate to enhance its barrier performance. 30 Remarkably, there are no existing works in the current literature that investigate the inuence of acid type on hydrolysis degree and structural characteristics of BCNCs intended for integration into biopolymeric matrices to enhance their inherent barrier properties. Hence, this study addresses, for the rst time, the development and application of a bionanocomposite coating formulation with low oxygen permeability attributes by utilizing acid-derived cellulose nanocrystals of bacterial origin (K. sucrofermentans).…”

Cinnamon Essential Oil Encapsulated into a Fish Gelatin-Bacterial Cellulose Nanocrystals Complex and Active Films Thereof

“…This was confirmed by the observations of Tongnuanchan et al [19] and Yao et al [45], who reported a decrease in transparency for fish skin gelatin films incorporated with citrus EO and gelatinchitosan films supplemented with D-Limonene. From a practical point of view, the haze values recorded in our study for all the formulations were below a 3% value, which is the threshold to guarantee an adequate display of the product inside the package [46].…”

Nanocellulose, a Renewable Biobased Functional/Reinforcement Additive for Composite Coating Materials: A Review

“…CBH mainly targets the crystalline region of cellulose, while GB hydrolyzes the chains into glucose sugars. 40 Enzymatic hydrolysis combined with the mechanical preparation of NC has been moving in a highly promising direction in recent years. To make enzymatic hydrolysis a more viable option for large-scale production, efforts should focus on overcoming its high cost.…”