Cellulose esterification with carboxylic acid in deep eutectic solvent pretreatment inhibits enzymatic hydrolysis

A designed ZrOCl2/ethylene glycol deep eutectic solvent for efficient lignocellulose valorization

Deep eutectic solvents (DESs) hold great potential in biorefining because they can efficiently deconstruct the recalcitrant structure of lignocellulose. In particular, inorganic salts with Lewis acids have been proven to be effective at cleaving lignin-carbohydrate complexes. Herein, a Zr-based DES system composed of metal chloride hydrate (ZrOCl2·8H2O) and ethylene glycol (EG) was designed and used for poplar powder pretreatment. Zr4+-based salts provide sufficient acidity for lignocellulose depolymerization. The acidity of the DES was analysed by the Kamlet-Taft solvatochromic parameter, and the results demonstrated that the acidity can be regulated by the DES composition. Under the optimum conditions (ZrOCl2·8H2O:EG molar ratio of 1:2), the DES pretreatment removes nearly 100 % hemicellulose and 94.7 % lignin. The recovered lignin exhibited a low polydispersity of 1.7. The cellulose residues deliver an efficiency of 94.4 % upon enzymatic digestion. Moreover, the DES can be easily recovered with high yield and purity, and the recycled DES still maintains high delignification and enzymatic hydrolysis efficiencies. The proposed DES pretreatment technology is promising for biomass valorization.

Preparation of cellulose-based flexible SERS and its application for rapid and ultra-sensitive detection of thiram on fruits and vegetables

In response to the prevalent issue of thiram as a common pesticide residue on the surface of fruits and vegetables, our research team employed an acidic hydrated metal salt low co-fusion solvent to dissolve cellulose lysis slurry. Subsequently, a regenerated cellulose membrane (RCM) was successfully prepared via sol-gel method. Uniformly sized Ag nanoparticles (NPs) were deposited on RCM utilizing the continuous ion layer adsorption and reaction (SILAR) technique. The resulting Ag NPs/RCM flexible surface-enhanced Raman spectroscopy (SERS) substrates exhibited a minimum detection limit of 5 × 10-9 M for Rhodamine 6G (R6G), demonstrating good uniformity (RSD = 4.86 %) and reproducibility (RSD = 3.07 %). Moreover, the substrate displayed a remarkable sensitivity of 10-10 M toward thiram standard solution. Given its inherent flexibility, the substrate proves advantageous for the detection of three-dimensional environments such as fruit and vegetable surfaces, and its practicality has been confirmed in the detection of thiram residue on apples, tomatoes, pears, and other fruits and vegetables.

Robust fabrication of sulfonated graphene oxide/poly (ether sulfone) catalytic membrane reactor for efficient cellulose hydrolysis and product separation

The efficient conversion of cellulose to high value-added products is important for the utilization of cellulose biomass. Achieving efficient cellulose hydrolysis and timely products separation is the essential target. Herein, a modified sulfonated graphene oxide/polydopamine deposited polyethersulfone (mGO(SO3H)-PDA/PES) membrane reactor, combining in the same unit a conversion effect and a separation effect, was prepared by suction filtration and subsequent polymerization and adhesion. The structure of PES membrane and deposition of PDA was regulated to sure that small molecules can pass through the membrane, while cellulose could not. As a result, the mGO(SO3H)-PDA/PES membrane realized the efficient cellulose hydrolysis and timely products separation under cross-flow circulation mode at 0.1 MPa, avoiding the further degradation of reducing sugar products. The yields of total reducing sugar (TRS) and glucose in separated hydrolysate reached 93.2 % and 85.5 %, respectively. This strategy provides potential guidance for efficient conversion of cellulose.

Progress in the Preparation of Stimulus-Responsive Cellulose Hydrogels and Their Application in Slow-Release Fertilizers

Agriculture is facing challenges such as water scarcity, low fertilizer utilization, food security and environmental sustainability. Therefore, the development of slow-release fertilizer (SRF) with controlled water retention and release is particularly important. Slow-release fertilizer hydrogel (SRFH) has a three-dimensional (3D) network structure combined with fertilizer processing, displaying excellent hydrophilicity, biocompatibility and controllability. Cellulose has abundant hydroxyl groups as well as outstanding biodegradability and special mechanical properties, which make it a potential candidate material for the fabrication of hydrogels. This work would analyze and discuss various methods for preparing stimulus-responsive cellulose hydrogels and their combinations with different fertilizers. Moreover, the application and release mechanism of stimulus-responsive cellulose hydrogels in SRF have been summarized as well. Finally, we would explore the potential issues of stimulus-responsive cellulose hydrogels serving as an SRF, propose reasonable solutions and give an outlook of the future research directions.

Application of Nanocellulose-Based Aerogels in Bone Tissue Engineering: Current Trends and Outlooks

The complex or compromised bone defects caused by osteomyelitis, malignant tumors, metastatic tumors, skeletal abnormalities, and systemic diseases are difficult to be self-repaired, leading to a non-union fracture. With the increasing demands of bone transplantation, more and more attention has been paid to artificial bone substitutes. As biopolymer-based aerogel materials, nanocellulose aerogels have been widely utilized in bone tissue engineering. More importantly, nanocellulose aerogels not only mimic the structure of the extracellular matrix but could also deliver drugs and bioactive molecules to promote tissue healing and growth. Here, we reviewed the most recent literature about nanocellulose-based aerogels, summarized the preparation, modification, composite fabrication, and applications of nanocellulose-based aerogels in bone tissue engineering, as well as giving special focus to the current limitations and future opportunities of nanocellulose aerogels for bone tissue engineering.