Modern technology has enabled the isolation of nanocellulose from plant-based fibers, and the current trend focuses on utilizing nanocellulose in a broad range of sustainable materials applications. Water is generally seen as a detrimental component when in contact with nanocellulose-based materials, just like it is harmful for traditional cellulosic materials such as paper or cardboard. However, water is an integral component in plants, and many applications of nanocellulose already accept the presence of water or make use of it. This review gives a comprehensive account of nanocellulose–water interactions and their repercussions in all key areas of contemporary research: fundamental physical chemistry, chemical modification of nanocellulose, materials applications, and analytical methods to map the water interactions and the effect of water on a nanocellulose matrix.

Cellulosic nanofibrils (CNFs) were isolated from one of the most widespread freshwater macroalgae, Aegagropila linnaei. The algae were first carboxylated with a recyclable dicarboxylic acid, which facilitated deconstruction into CNFs via microfluidization while preserving the protein component. For comparison, cellulosic fibrils were also isolated by chemical treatment of the algae with sodium chlorite. Compared with the energy demanded for deconstruction of wood fibers, algal biomass required substantially lower levels. Nevertheless, the resultant nanofibrils were more crystalline (crystallinity index > 90%) and had a higher degree of polymerization (DP > 2500). Taking advantage of these properties, algal CNFs were used to produce films or nanopapers (tensile strength of up to 120 MPa), the strength of which resulted from protein-enhanced interfibrillar adhesion. Besides being translucent and flexible, the nanopapers displayed unusually high thermal stability (up to 349 °C). Overall, we demonstrate a high-end utilization of a renewable bioresource that is available in large volumes, for example, in the form of algal blooms.

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Biosystems and bioprocesses are typically not connected to arid areas, where the produced biomass and its availability are low. There is however a large potential for arid areas to become major bioeconomical actors via more localized biomass generation strategies. Indoor farming, bioengineering, and aquaculture have a great potential to be at the center of this transition. They are expected to address important challenges associated with food and (bio)­materials supply and, ultimately, to climate and environment. Specifically, the utilization of the by- and coproducts deriving from these strategies could synergistically connect into a range of circular processes toward sustainable bioproducts’ supply and the greening of arid areas. These topics are at the center of this perspective, where emerging biomass generation and management strategies in arid areas are introduced. The potential positive feedback loops between their coproducts are then put in relation with the development of more diverse and thriving biosystems as well as the generation of a range of bioproducts. These approaches are contextualized with the current and alternative energy sectors and water treatments processes, which have well-established economical portfolios across most arid areas. The mapping of innovative bioeconomical actors in arid areas and their synergistic interactions, as put forward herein aims to intensify research efforts toward a fully integrated and global sustainable bioeconomy.