Development of a Multi-Enzymatic Approach for the Modification of Biopolymers with Ferulic Acid

Abstract

A series of polymers, including chitosan (CS), carboxymethylcellulose (CMC) and a chitosan–gelatin (CS–GEL) hybrid polymer, were functionalized with ferulic acid (FA) derived from the enzymatic treatment of arabinoxylan through the synergistic action of two enzymes, namely, xylanase and feruloyl esterase. Subsequently, the ferulic acid served as the substrate for laccase from Agaricus bisporus (AbL) in order to enzymatically functionalize the above-mentioned polymers. The successful grafting of the oxidized ferulic acid products onto the different polymers was confirmed through ultraviolet–visible (UV–Vis) spectroscopy, attenuated total reflectance (ATR) spectroscopy, scanning electron microscopy (SEM) and nuclear magnetic resonance (NMR) spectroscopy. Additionally, an enhancement of the antioxidant properties of the functionalized polymers was observed according to the DDPH and ABTS protocols. Finally, the modified polymers exhibited strong antimicrobial activity against bacterial populations of Escherichia coli BL21DE3 strain, suggesting their potential application in pharmaceutical, cosmeceutical and food industries.

Development of Low-Density Polyethylene Films Coated with Phenolic Substances for Prolonged Bioactivity

“…The next goal of the current study was to define the composition of the coating solution to enable its quick drying without substantial loss of bioactivity. As shown in a preliminary study, coatings prepared purely with the bioactive substance and water/alcohol as solvent did not show any inhibition against E. coli, and this was mainly linked with the evaporation of the solvent during the drying process and the subsequent loss of the volatile bioactive substances (mainly in carvacroland thymol-based solutions) [44]. The use of Tween 80/glycerol was suggested as a potential solution to improve the antimicrobial response of the coatings [32].…”

“…In the case of OLE-based coatings, methanol was used as a solvent and the amount of OLE was increased to 20% w/w based on the antimicrobial response of the bioactive substances (see Figure 1). The type of solvent used to dilute the bioactive substances was based on initial results [44]. An equal amount of solvent (water or alcohol) was used in MC-and bioactive-based solutions.…”

“…More specifically, from the onset of the exponential phase, the growth of E. coli is inhibited especially for concentrations higher than 80 µg/mL of carvacrol or thymol and 400 µg/mL of OLE. Since OLE is a mixture of phenolic and non-phenolic compounds, its inhibition ability against E. coli is lower than the respective inhibition of carvacrol/thymol [44]. Based on the above and with the aim to obtain similar levels of inhibition from the prepared coatings, the final concentration of carvacrol-/thymol-based coating was set at 5% w/w and 20% w/w of OLE with respect to the weight of LDPE.…”

“…Since phenolic-based substances are highly soluble in alcohols, their dissolution was performed in an alcoholic medium (ethanol or methanol). To increase the affinity of the less polar thymol and carvacrol with water, the current research group identified the appropriate type of solvent and the need of using an emulsifier for the preparation of bioactive coatings with wetting ability on LDPE and an antimicrobial response [44]. However, the bioactive solutions using an emulsifier as a reagent resulted in "semi-dry" coatings, which limits their industrial potential.…”

From waste to resource: advancements in sustainable lignin modification

“…17 The isolated lignin can eventually be sulfonated by replacing a hydroxyl group with a sulfonate group. 18 The lignosulfonate lignin is water-soluble and can be separated from the rest of the biomass. On the other hand, the soda process has seen extensive pilot trials.…”