Nanocrystalline cellulose from Arctic brown algae Laminaria digitata and Saccharina latissima

Abstract

Nanocrystalline cellulose (NCC) was successfully obtained from two Arctic brown algae species, Laminaria digitata and Saccharina latissima. The production process involved a sequential extraction of non-cellulosic compounds, an environmentally friendly bleaching process with hydrogen peroxide, and subsequent acidic hydrolysis, resulting in the formation of nanosized rod-like particles. Comprehensive assessments were conducted to evaluate the influence of hydrolysis conditions, specifically using hydrochloric and sulfuric acids, on the key characteristics of the nanocellulose. The resulting NCC was characterized using various techniques including Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), thermogravimetric analysis (TGA, DTG), scanning electron microscopy (SEM), laser diffraction, and low-temperature nitrogen sorption. The obtained algal NCC demonstrated a yield of 76–91%, a degree of polymerization of 150–230 units, and a crystallinity index of 69–80%. The choice of acid during the production significantly influenced the thermal stability, particle size distribution, and porous properties of the samples. Remarkably, the algal NCC, acquired in the form of stable gel-like suspensions, exhibited robust stability during extended storage. These materials showcase promising potential for applications in biomedicine, serving as versatile components for hydro/aerogels, matrices, and fillers in the development of advanced medical dressings.