Lignocellulosic materials(LCMs),abundant biomass residues,pose significant environmental challenges when improperly disposed of.LCMs,such as sugarcane bagasse,rice straw,saw dust and agricultural residues,are abun-dant but often burned,contributing to air pollution and greenhouse gas emissions.This review explores the potential of transforming these materials into high-value carbon nanomaterials(CNMs).We explore the potential of transforming these materials into high-value CNMs.By employing techniques like carbonization and activa-tion,LCMs can be converted into various CNMs,including carbon nanotubes(CNTs),graphene(G),graphene oxide(GO),carbon quantum dots(CQDs),nanodiamonds(NDs),fullerenes(F),carbon nanofibers(CNFs),and others.Hybridizing different carbon allotropes further enhances their properties.CNMs derived from cellulose,lignin,and hemicellulose exhibit promising applications in diversefields.For instance,CNTs can be used in energy storage devices like batteries and supercapacitors due to their exceptional electrical conductivity and mechanical strength.Additionally,CNTs can be incorporated into recycled paper as afire retardant additive,enhancing itsflame resistance.G,renowned for its high surface area and excellent electrical conductivity,finds applications in electronics,sensors,catalysis,and water treatment,where it can be used to adsorb heavy metal ions.CQDs,owing to their unique optical properties,are used in bioimaging,drug delivery,and optoelectronic devices.By harnessing the potential of LCMs,we can not only mitigate environmental concerns but also contri-bute to a sustainable future.Continued research is essential to optimize synthesis methods,explore novel applica-tions,and unlock the full potential of these versatile materials.
利用木质纤维素生产燃料和化学品是解决现阶段能源危机的有效途径之一。尽管木质纤维素的预处理技术受到广泛研究,但传统预处理技术的高能源需求、高成本以及设备抗腐蚀技术的限制催生了新型预处理工艺的发展。低共熔溶剂(deep eutectic solvents,DES)的出现有效地解决了这些问题,并大大提高了木质纤维素的转化效率。目前,二元低共熔溶剂(binary deep eutectic solvents,BDES)的应用与研究较为广泛,效率更高且具有针对性的三元低共熔溶剂(ternary deep eutectic solvents,TDES)也在逐渐发展中。本研究对TDES进行了系统的分类(包括含醇和酸的TDES、含有机分子化合物的TDES、含金属卤化物的TDES和含有两种不同酸的TDES),探讨了上述TDES在木质纤维素预处理后酶解性能改善方面的研究进展,同时对联合预处理方法进行了综述,并展望了DES在不同研究方向的应用潜力。
Developing a cost-effective and environmentally friendly process for the production of valuable chemicals from abundant herbal biomass receives great attentions in recent years.Herein,taking advantage of the“lignin first”strategy,corn straw is converted to valuable chemicals including lignin monomers,furfural and 5-methoxymethylfurfural via a two steps process.The key of this research lies in the development of a green and low-cost catalytic process utilizing magnetic Raney Ni catalyst and high boiling point ethylene glycol.The utilization of neat ethylene glycol as the sole slovent under atmospheric conditions obviates the need for additional additives,thereby facilitating the entire process to be conducted in glass flasks and rendering it highly convenient for scaling up.In the initial step,depolymerization of corn straw lignin resulted in a monomer yield of 18.1 wt%.Subsequently,in a dimethyl carbonate system,the carbohydrate component underwent complete conversion in a one-pot process,yielding furfural and 5-methoxymethylfurfural as the primary products with an impressive yield of 47.7%.
The bioconversion of lignocellulose has attracted global attention,due to the significant potential of agricultural and forestry wastes as renewable zero-carbon resources and the urgent need for substituting fossil carbon.The cellulosome system is a multi-enzyme complex produced by anaerobic bacteria,which comprises cellulases,hemicellulases,and associated enzymatic and non-enzymatic components that promote biomass conversion.To enhance their efficiency in degrading recalcitrant lignocellulosic matrices,cellulosomes have been employed to construct biocatalysts for lignocellulose bioconversion,such as consolidated bioprocessing and consolidated bio-saccharification.Hemicelluloses,the second most abundant polysaccharides in plant cell walls,hold valuable application potential but can also induce inhibitory effects on cellulose hydrolysis,thus highlighting the indispensable roles of hemicellulases within the cellulosome complex.This review evaluated current research on cellulosomal hemicellulases,comparing their types,abundance,and regulation,primarily focusing on eight known cellulosome-producing species of different origins.We also reviewed their growth conditions,their hemicellulose-degrading capabilities,and the inhibitory effects of hemicellulose on cellulosome-based lignocellulose saccharification.Finally,we proposed strategies for targeted enhancement of hemicellulase in cellulosomes to improve lignocellulose bioconversion in future studies.
Min XiaoYa-Jun LiuEdward A.BayerAkihiko KosugiQiu CuiYingang Feng
