GRAPE LIGNIN BASED HYDROGELS

conference proceedings

English

Lignin is an amorphous and highly heterogeneous aromatic polymer. Lignin, cellulose, hemicellulose, pectin, and a small number of proteins and lipids are involved in creating lignocellulosic biomass, the most abundant renewable resource on the earth. In general, lignin accounts for 15-35% of dry weight in most terrestrial plants depending on its origin, species, age and growing conditions [1],[2]. It plays an essential role in the composition of the cell wall of vascular plants, which files it in the group of the most abundant polymers in nature. It provides compressive trength to the plant tissues, rigidity to the cell walls, resistance to insects and pathogens and decreases water’s permeation through the cell walls. The highest content of lignin in nature is in softwoods (up to 33%) and hardwoods (up to 25%) [3]. Lignin is a unique phenolic aromatic polymer with a threedimensional network and various functional groups [2],[4]. One of the most significant advantages of lignin is its antimicrobial and antioxidant activity, which is linked to its chemical composition and structure. While antioxidant activity is detected in all types of lignin, antimicrobial activity is not guaranteed and depends on the type of lignin [5],[6]. Regarding the properties of lignin, extensive efforts have been made to develop new materials, such as hydrogels, which are 3D hydrophilic physically or chemically cross-linked polymer networks. Hydrogels may have a structure similar to the macromolecular composition of the human body’s tissues [7]. Their functional properties can be notably improved by adding lignin with antimicrobial and antioxidant properties. In addition, lignin can modify the final mechanical properties of hydrogels [8]. In our research, we have isolated lignin from grape pomace that is largely available in the Czech Republic, especially in South Moravia region, as a waste product after a production of wines. Production of 6 L of wine generates 1 kg of grape pomace with a content of 200 – 300 g of lignin [9],[10]. For example, in 2021 were produced approximately 618 thousand hectolitres of wine in the Czech Republic [11]. This work summarises the chemical and physical properties of isolated grape lignin and shows the effect of grape lignin addition on the properties of gellan hydrogels. The gellan hydrogels modified by grape lignin showed improved rheological properties compared to neat gellan hydrogels. Moreover, gellan/lignin hydrogels showed antioxidant and antimicrobial activity. Based on the properties of these hydrogels, their potential use is wide, for example in medicine as drug delivery systems, bio-compatible coating on medical implants, in tissue engineering applications as scaffolds or wound healing patches. However, it seems possible to use it in another department, specifically as heavy metal ion removal from ontaminated water.

Lignin; hydrogels, grape pomace

ČERNEKOVÁ, N.; VOSTREJŠ, P.; KOVALČÍK, A.

23. 11. 2022

978-80-8208-083-7

Chémia a technológie pre život, 24. celoslovenská študentská vedecká konferencia s medzinárodnou účasťou

SLOVENSKÁ TECHNICKÁ UNIVERZITA V BRATISLAVE

první

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