Shanshan Liu

Lignocellulosic agro-forestry residues (LARs), such as rice straw, sugarcane bagasse, and wood wastes, are abundant and low-cost feedstocks for polyhydroxyalkanoate (PHA) bioplastics. However, their complex cellulose–hemicellulose–lignin matrix requires integrated valorization strategies. This review presents a dual-framework approach: “pretreatment–co-substrate compatibility” and “pretreatment–microbial platform matching”, to align advanced pretreatment methods (including deacetylation–microwave integration, deep eutectic solvents, and non-sterilized lignin recovery) with engineered or extremophilic microbial hosts. A “metabolic interaction” perspective on co-substrate fermentation, encompassing dynamic carbon flux allocation, synthetic consortia cooperation, and one-pot process coupling, is used to elevate PHA titers and tailor copolymer composition. In addition, we synthesize comprehensive kinetic analyses from the literature that elucidate microbial growth, substrate consumption, and dynamic carbon flux allocation under feast–famine conditions, thereby informing process optimization and scalability. Microbial platforms are reclassified as broad-substrate, process-compatible, or product-customized categories to emphasize adaptive evolution, CRISPR-guided precision design, and consortia engineering. Finally, next-generation techno-economic analyses, embracing multi-product integration, regional adaptation, and carbon-efficiency metrics, are surveyed to chart viable paths for scaling LAR-to-PHA into circular bioeconomy manufacturing.

Nitrification inhibitor is essential for increasing the nitrogen utilization efficiency of agricultural plants, thus reducing environmental pollution and increasing crop yield. However, the easy volatilization and limited functional property is still the bottleneck of nitrification inhibitors. Herein, a novel water-soluble polymeric nitrification inhibitor was synthesized through the copolymerization of acrylamide and bio-based acrylic acid, which was synthesized from biomass-derived furfural, and the complexation of carboxyl groups and 3,4-dimethylpyrazole. The results showed that the nitrification inhibitor was an amorphous polymer product with a glass transition temperature of 146 °C and a thermal decomposition temperature of 176 °C, and the content of 3,4-dimethylpyrazole reached 2.81 wt%, which was 115% higher than our earlier product (1.31 wt%). The polymeric nitrification inhibitor can inhibit the activity of ammonia-oxidizing bacteria effectively, thus inhibiting the conversion of ammonium nitrogen to nitrate nitrogen and converting the insoluble phosphate into soluble and absorbable phosphate. By introducing a copolymer structure with a strong flocculation capacity, the polymeric nitrification inhibitor is further endowed with a soil-loosening function, which can increase the porosity of soil to improve the soil environment. Therefore, the nitrification inhibitor can be used in water-soluble and liquid fertilizers, as well as in high tower melting granulated compound fertilizers.

Lignin-containing nanocellulose fibers (LCNF) have been considered as a valuable enhancer for polyacrylic acid (PAA)-based hydrogels that can form rigid porous network structures and provide abundant polar groups. However, the PAA–LCNF hydrogel is dominated by a single-network (SN) structure, which shows certain limitations when encountering external environments with high loads and large deformations. In this paper, sodium alginate (SA) was introduced into the PAA–LCNF hydrogel network to prepare a double-network (DN) hydrogel structure of the SA-Ca²⁺ and PAA–LCNF through a two-step process. The covalent network of PAA–LCNF acts as the resilient framework of the hydrogel, while the calcium bridging networks of SA, along with the robust hydrogen bonding network within the system, function as sacrificial bonds that dissipate energy and facilitate stress transfer. The resulting hydrogel has porous morphologies. Results show that SA can effectively improve the mechanical properties of DN hydrogels and endow them with excellent thermal stability and electrical conductivity. Compared with pure PAA–LCNF hydrogel, the elongation at break of DN hydrogel increased from 3466% to 5607%. The good electrical conductivity makes it possible to use the flexible sensors based on DN hydrogel to measure electrophysiological signals. Our results can provide a reference for developing multifunctional hydrogels that can withstand ultra large deformation.

The valorization of the black liquor produced during the chemical pulping of wheat straw is the key to the sustainable use of this abundant agricultural waste. However, the silica problem has hampered the recovery process. Herein, nanoprecipitation technology was used to produce lignin nanoparticles (LNPs) from wheat straw black liquor using γ-valerolactone (GVL) as a solvent and water as an anti-solvent. The results showed that a uniform, well-dispersed, and stable LNP was produced. The particle size and Zeta potential of 161 nm and −24 mV of the LNP suspension were obtained at a GVL concentration of 87%. The chemical structure and bonding of the lignin were adequately preserved after nanoprecipitation based on two-dimensional heteronuclear single quantum coherence nuclear magnetic resonance (2D-HSQC NMR) spectroscopy, Fourier transform infrared (FTIR) analysis, and thermal stability was improved based on thermogravimetric analysis. In addition, the abundant phenolic hydroxyl groups of LNP quantified by ³¹P-NMR analysis are beneficial for chemical cross-linking and modification. This work not only achieved the valorization of wheat straw black liquor but also opened up a new avenue for advanced nanomaterials.

In this study, a novel amphiphilic KL-AA-MMA nanoparticle was prepared through the graft copolymerization of kraft lignin (KL) with acrylic acid (AA) and methyl methacrylate (MMA), using potassium persulfate as an initiator in a water/dimethyl sulfoxide solvent medium, which was followed by the nanoprecipitation technique using dimethylformamide as a solvent and deionized water as an antisolvent. The successful graft polymerization was verified by ¹H-nuclear magnetic resonance (NMR), ³¹P-NMR, and Fourier transform infrared (FTIR) analyses; and the grafting yield of the generated KL-AA-MMA copolymer ranged from 68.2% to 96.5%. Transmission electron microscopy (TEM) observation revealed the formation of amorphous KL-AA-MMA nanoparticles. Additionally, KL-AA-MMA9 nanoparticles with the highest yield exhibited the minimum hydrodynamic diameter and polydispersity of 261 nm and 0.153, respectively. Moreover, the amphiphilicity of KL-AA-MMA nanoparticles was significantly improved by the grafting of MMA monomers. Finally, the adsorption performance of KL-AA-MMA nanoparticles at the xylene interface was evaluated by a quartz crystal microbalance with dissipation (QCM-D). The results demonstrated that the most amphiphilic sample, KL-AA-MMA9 nanoparticles, with the smallest hydrodynamic size displayed the highest adsorption on the oil/water interface. This product provides a wide range of applications in oil/water emulsions.

In this study, the effect of a combined treatment consisting of calcium hydroxide (CH) followed by activated carbon (AC) on the purification of hemicellulose in the pre-hydrolysis liquor (PHL) from pulping process has been evaluated. The results show that lignin and furfural of PHL are efficiently removed, and the lignin removal is achieved by forming complexes onto CH particles in the CH treatment process, while acetic acid (acetate) is formed from the hydrolysis of acetyl groups present in the dissolved hemicelluloses in the PHL. The loss of xylo-oligosaccharides (XOS) is moderate, even at a high CH dosage of 0.8% while the xylose concentration is essentially unchanged. For the AC treatment, the optimal treating pH can enhance the interactions between AC and residual lignin and change the zeta potential of AC resulting in improved lignin adsorption onto AC. An increase of AC dosage has the tendency to adsorb more XOS_DP>6 than XOS_DP2~6. Overall, 66.9% of lignin and 70.1% of furfural removals are achieved under the optimal conditions of CH and AC treatment process, with a 5.9% total xylosugars loss. The present combination of CH and AC treatment process was more effective and selective for purification of xylosugars of PHL.