Poly(vinyl alcohol) hydrogels have a long and successful history of applications in biomedicine. Historically, these matrices were developed to be nondegradable—limiting their utility to applications as permanent implants. For tissue engineering and drug delivery, herein we develop spontaneously eroding physical hydrogels based on PVA. We characterize in detail a mild, noncryogenic method of producing PVA physical hydrogels using poly(ethylene glycol) as a gelating agent, and investigate PVA molar mass as a means to define the kinetics of erosion of these biomaterials. PVA hydrogels are characterized for associated inflammatory response in adhering macrophages, antiproliferative effects mediated through delivery of cytotoxic drugs to myoblasts, and pro-proliferative activity achieved via presentation of conjugated growth factors to endothelial cells. Together, these data present a multiangle characterization of these novel multifunctional matrices for applications in tissue engineering and drug delivery mediated by implantable biomaterials.

The goal of this study is to assess Ziziphus lotus’s potential for producing carboxymethylcellulose adsorption membranes with the ability to adsorb methyl green from wastewaters by the revalorization of its cellulosic fraction. The cellulose from this feedstock was extracted by an alkaline process and TAPPI standard technique T 203 cm-99 and afterwards they were carboxymethylated. The obtained carboxymethylcelluloses were deeply characterized, being observed that the carboxymethylcellulose produced from the alkaline cellulose presented the higher solubility due to its lower crystallinity degree (53.31 vs. 59.4%) and its higher substitution degree (0.85 vs. 0.74). This carboxymethylcellulose was cross-linked with citric acid in an aqueous treatment in order to form an adsorption membrane. The citric acid provided rigidity to the membrane and although it was hydrophilic it was not soluble in water. By evaluating the potential of the produced membrane for the removal of pollutant dyes from wastewater, it was observed that the adsorption membrane prepared from the carboxymethylcellulose’s produced from the Ziziphus lotus was able to remove 99% of the dye, methyl green, present in the wastewater. Thus, this work demonstrates the potential of the Ziziphus lotus for the production of a novel and cost-effective carboxymethylcellulose adsorption membrane with high capacity to treat wastewaters.

Apple pomace is an abundant agro-industrial residue rich in oligosaccharides, whose efficient and sustainable extraction remains challenging. To overcome these limitations, this study delivers a novel biorefinery strategy by coupling ultrasound-assisted extraction pretreatment with optimised microwave-assisted hydrolysis. Through response surface methodology, the optimal microwave hydrolysis extraction conditions were achieved at 20 min and 120 °C. The obtained oligosaccharides presented a molecular-weight of 191,071 Da, a polydispersity index of 2.19 and a high content of galacturonyl groups (9.95 g/L) and arabino substituents (7.27 g/L). Furthermore, a biphasic system was applied at the optimal point obtained for the monophasic system in order to examine its potential for selective oligosaccharide fractionation. In this case, the galacturonic acid did not form part of the obtained oligosaccharides, and instead they were predominantly formed by galactose and arabinose (6.55 and 4.48 g/L respectively). Moreover, this biphasic setup yielded fewer polydisperse fractions with a lower content of degradation products. Overall, this work highlights the promise of optimised microwave-assisted hydrolysis as a sustainable strategy for oligosaccharide valorisation from apple pomace while demonstrating that the extension to a biphasic system represents a promising alternative for improving process selectivity.

Commercial value. This positions biomass as a key source for energy production as well as for the generation of high-value-added products. The present special issue, entitled "Valorization of Biomass: Towards the Production of Fine Chemicals and Materials", compiles several examples that illustrate the remarkable versatility of biomass as a source of various compounds, contributing to a sustainable chemical engineering industry.The main aim of this research topic is to investigate innovative strategies for the valorization of biomass through the production of fine chemicals and materials. This involves employing emerging technologies or the use of unconventional and underexplored feedstocks. These approaches aim to provide sustainable alternatives to fossil-derived products, contributing to the development of a circular bioeconomy by transforming the main components of the biomass into high-value-added products.The contributions highlighted in this special issue demonstrate the potential of non-traditional biomass sources and present environmentally-friendly and economically viable processes with promising scalability for industrial implementation. Collectively, these contributions underscore the feasibility of integrating novel biomass conversion pathways into existing value chains, thereby enhancing the sustainability and resilience of chemical and materials manufacturing.With the aim of enhancing the enzymatic hydrolysis of brewers' spent grain (BSG), which is a lignocellulosic by-product abundantly generated by the beverage industry, Castilla-Archilla et al., proposed a novel and environmentally conscious pretreatment. The research focuses on the application of a dilute acid thermal pretreatment using hydrochloric acid (HCl) as an alternative to the conventionally employed sulfuric acid (H₂SO₄), aiming to reduce the generation of compounds typically associated with harsher acid treatments that could inhibit the fermentation of the carbohydrates obtained in the enzymatic hydrolysis.The pretreatment was optimized to achieve maximal disruption of the lignocellulosic matrix, thereby improving enzyme accessibility, while simultaneously minimizing the reagents and energy requirements. The pretreated BSG obtained exhibited significantly enhanced susceptibility to enzymatic hydrolysis, yielding a high concentration of fermentable carbohydrates. These sugars serve as valuable substrates for microbial fermentation, enabling the biosynthesis of a wide range of fine chemicals. This valorization pathway positions brewers' spent grain not only as a low-cost and sustainable feedstock, but also as a promising candidate for biorefinery applications in the context of circular bioeconomy development.In their comprehensive review, Ojewumi et al., explore the diverse strategies employed for the conversion of waste paper, which is an abundant component of the municipal solid wastes, into fermentable carbohydrates. Due to its inherently recalcitrant lignocellulosic structure, waste paper requires an effective pretreatment step to enhance the efficiency of the subsequent enzymatic hydrolysis. The review compiles various sustainable pretreatment methodologies, encompassing chemical, physical, and biological approaches, all aimed at disrupting the structural integrity of the biomass to improve enzyme accessibility. In addition, it provides a critical analysis of enzymatic hydrolysis studies conducted on pretreated waste paper, highlighting the drawbacks of this process and proposing potential strategies to mitigate them.By offering an integrated perspective on the valorization of waste paper, this review underscores its potential as a renewable carbohydrate-rich feedstock. The liberated sugars can be harnessed for the microbial synthesis of value-added bioproducts, such as bioethanol, positioning waste paper as a viable resource within the circular bioeconomy and biorefinery frameworks.In their study, Adeoti et al., present a promising strategy to reduce modern society's reliance on fossil-derived resources through the development of biolubricants as sustainable alternatives to conventional mineral oils. The proposed approach involves the transesterification of oil extracted from the seeds of the underutilized Desert date (Balanites aegyptiaca), a resilient fruit species adapted to arid environments. The resulting biolubricants were thoroughly characterized, and their properties were evaluated in comparison with those of commercially available petroleumbased lubricants. The analysis revealed that the biolubricants derived from Desert date seed oil exhibit performance parameters compatible with automotive applications.Thus, this study not only highlights the potential of non-edible, underexploited biomass as a feedstock for high-value bioproducts, but also contributes to the advancement of greener technologies in the lubricant industry. By supporting biobased innovation, this research supports the transition toward a more sustainable and environmentally responsible industry.The study led by Santos et al., investigates the chemical and anatomical characteristics of the wood from two native Brazilian tree species-Cabralea canjerana and Cordia americana-with the aim of exploring their potential as novel bioresources. While extracts from these species have traditionally been employed as natural dyes, preservatives, and in medicine, their precise chemical profiles had not been thoroughly elucidated prior to this research.To address this knowledge gap, the authors performed a comprehensive chemical and anatomical analysis and applied gas chromatography-mass spectrometry (GC-MS) to characterize the bioactive compounds obtained through a solvent extraction. This approach enabled the identification of several compounds with known pharmacological properties, shedding light on the therapeutic potential of these wood-derived extractives.By providing a detailed chemical and anatomical characterization,...