Comparison of lignin derivatives as substrates for laccase-catalyzed scavenging of oxygen in coatings and films

Abstract

BackgroundLignin derivatives are phenylpropanoid biopolymers derived from pulping and biorefinery processes. The possibility to utilize lignin derivatives from different types of processes in advanced enzyme-catalyzed oxygen-scavenging systems intended for active packaging was explored. Laccase-catalyzed oxidation of alkali lignin (LA), hydrolytic lignin (LH), organosolv lignin (LO), and lignosulfonates (LS) was compared using oxygen-scavenging coatings and films in liquid and gas phase systems.ResultsWhen coatings containing lignin derivatives and laccase were immersed in a buffered aqueous solution, the oxygen-scavenging capability increased in the order LO < LH < LA < LS. Experiments with coatings containing laccase and LO, LH or LA incubated in oxygen-containing gas in air-tight chambers and at a relative humidity (RH) of 100% showed that paperboard coated with LO and laccase reduced the oxygen content from 1.0% to 0.4% during a four-day period, which was far better than the results obtained with LA or LH. LO-containing coatings incubated at 92% RH also displayed activity, with a decrease in oxygen from 1.0% to 0.7% during a four-day period. The oxygen scavenging was not related to the content of free phenolic hydroxyl groups, which increased in the order LO < LS < LH < LA. LO and LS were selected for further studies and films containing starch, clay, glycerol, laccase and LO or LS were characterized using gel permeation chromatograpy, dynamic mechanical analysis, and wet stability.ConclusionsThe investigation shows that different lignin derivatives exhibit widely different properties as a part of active coatings and films. Results indicate that LS and LO were most suitable for the application studied and differences between them were attributed to a higher degree of laccase-catalyzed cross-linking of LS than of LO. Inclusion in active-packaging systems offers a new way to utilize some types of lignin derivatives from biorefining processes.

Laccase mediated oxidation of industrial lignins: Is oxygen limiting?

“…These results, together with similar observations by previous researchers suggest that the generation of many reactive species is not a determinant factor for enhanced polymerization. Nevertheless, in line with this study, Johansson et al [28] and Nugroho Prasetyo et al [7] noted that laccase-catalyzed reaction resulted in extensive polymerization of lignosulfonates as compared to organosolv and indulin lignins. Generally it can be concluded that the decrease in phenolic groups, fluorescence intensity and simultaneous general increase in treated lignin molecular weight are in line with similar changes observed by previous researchers [14,27].…”

Bio-printing cell-laden Matrigel–agarose constructs

“…Higher percentage of spreading cells (37%) was found when Matrigel fraction was 50%, which was consistent with a previous study of 3D colonoid culture in Matrigel. 13 Although hybrid hydrogel with 50% Matrigel supported more cells to spread and grow, it had poor printability due to the low G′ (Figures. 2(a) and S3(c)).…”

“…In fact, a previous study has shown that the growth of intestinal stem cells depends on the amount of Matrigel: the highest efficiency of colonoid formation (33 ± 5%) has been observed when 50% Matrigel is used. 13 …”

“…12 Protein-based hydrogels such as Matrigel contain necessary growth factors and peptides and can facilitate cell growth and adhesion in 3D matrix. 13–16 Recently, Matrigel-based long-term culture systems have been developed for intestinal stem cells. 17,18 However, Matrigel, like the majority of protein-based hydrogels, has poor mechanical properties and is not suitable for printing, 19 which significantly limits its application as a bio-ink for 3D printing.…”

Enzymatic‐assisted extraction and modification of lignocellulosic plant polysaccharides for packaging applications

“…This has been successfully implemented by the use of laccase (EC 1.10.3.2.). This enzyme crosslinks lignin associated aromatic residues, consequently increasing the molecular weight of the extracted polymer and improving the mechanical and barrier properties . Blends of spruce GGM and carboxymethylcellulose exhibited improved mechanical properties due to crosslinking with laccase .…”