Deep eutectic solvents from hemicellulose-derived acids for the cellulosic ethanol refining of Akebia' herbal residues

Comprehensive reutilization of Glycyrrhiza uralensis residue by extrusion-biological pretreatment for coproduction of flavonoids, cellulase, and ethanol

A continuous chemical-free green approach was investigated for the comprehensive reutilization of all components in herbal extraction residues (HERs), taking Glycyrrhiza uralensis residue (GUR) as an example. The GUR structural changes induced by mechanical extrusion which improve the specific surface area and enzyme accessibility of GUR. With 3 % pretreated GUR loading of high-tolerance Penicillium oxalicum G2. The reducing sugar yield of 11.45 g/L was achieved, along with an 81.06 % in situ enzymatic hydrolysis. Finally, 8.23 g/L bioethanol (0.40 g/g total sugar) was produced from GUR hydrolysates after 24 h fermentation of Pichia stipitis G32. The amount of functional medicinal ingredients extracted from GUR after hydrolysis (39.63 mg/g) was 37.69 % greater than that of un-pretreated GUR. In total, 1.49 g flavonoids, 294.36 U cellulase, and 14.13 g ethanol could be produced from 100 g GUR using this process, illustrating that this green and efficient process has the potential for industrial production.

Deep eutectic solvent pretreatment of cork dust - Effects on biomass composition, phenolic extraction and anaerobic degradability

In this study, phenolic compounds using deep eutectic solvents (DES) were extracted from cork dust, and the biogas production potential of DES-treated cork dust samples was determined. The DES treatment was carried out using choline chloride and formic acid (1:2 M ratio) at various temperatures (90, 110 and 130 °C) and treatment times (20, 40 and 60 min) at a solid-to-solvent ratio of 1:10 g mL-1. The highest total phenolic content (137 mg gallic acid equivalent (GAE) g-1 dry cork dust) was achieved at 110 °C/20 min. The extracts exhibited an antioxidant capacity of up to 56.3 ± 3.1 % 1,1-diphenyl-2-picrylhydazyl (DPPH) inhibition at a dilution rate of 100. DES treatment resulted in minimal sugar solubilization at low temperatures, while approximately 42 % of the xylan fraction in the biomass degraded under severe conditions (e.g., 130 °C/60 min). Catechin, 4-hydroxybenzoic acid and gallic acid were the major phenolics in DES extracts. The biogas yield of DES-treated cork dust increased with treatment severity. The highest biogas yield (115.1mLN gVS-1) was observed at 130 °C/60 min, representing an increase of 125 % compared to the untreated sample. SEM images revealed that the surface structure of the samples became smoother after mild pretreatment and rougher after harsh pretreatment. Compositional and FTIR analyses indicated that a higher biogas formation potential was associated with increased cellulose content in the substrate, which could be attributed to hemicellulose solubilization in the hydrolysate. Overall, DES pretreatment effectively enhanced phenol extraction and anaerobic degradability.

Sustainable biorefinery approach by utilizing xylose fraction of lignocellulosic biomass

Lignocellulosic biomass (LCB) has been a lucrative feedstock for developing biochemical products due to its rich organic content, low carbon footprint and abundant accessibility. The recalcitrant nature of this feedstock is a foremost bottleneck. It needs suitable pretreatment techniques to achieve a high yield of sugar fractions such as glucose and xylose with low inhibitory components. Cellulosic sugars are commonly used for the bio-manufacturing process, and the xylose sugar, which is predominant in the hemicellulosic fraction, is rejected as most cell factories lack the five‑carbon metabolic pathways. In the present review, more emphasis was placed on the efficient pretreatment techniques developed for disintegrating LCB and enhancing xylose sugars. Further, the transformation of the xylose to value-added products through chemo-catalytic routes was highlighted. In addition, the review also recapitulates the sustainable production of biochemicals by native xylose assimilating microbes and engineering the metabolic pathway to ameliorate biomanufacturing using xylose as the sole carbon source. Overall, this review will give an edge on the bioprocessing of microbial metabolism for the efficient utilization of xylose in the LCB.

Lignocellulosic Biomass for the Fabrication of Triboelectric Nano-Generators (TENGs)-A Review

Growth in population and increased environmental awareness demand the emergence of new energy sources with low environmental impact. Lignocellulosic biomass is mainly composed of cellulose, lignin, and hemicellulose. These materials have been used in the energy industry for the production of biofuels as an eco-friendly alternative to fossil fuels. However, their use in the fabrication of small electronic devices is still under development. Lignocellulose-based triboelectric nanogenerators (LC-TENGs) have emerged as an eco-friendly alternative to conventional batteries, which are mainly composed of harmful and non-degradable materials. These LC-TENGs use lignocellulose-based components, which serve as electrodes or triboelectric active materials. These materials can be derived from bulk materials such as wood, seeds, or leaves, or they can be derived from waste materials from the timber industry, agriculture, or recycled urban materials. LC-TENG devices represent an eco-friendly, low-cost, and effective mechanism for harvesting environmental mechanical energy to generate electricity, enabling the development of self-powered devices and sensors. In this study, a comprehensive review of lignocellulosic-based materials was conducted to highlight their use as both electrodes and triboelectric active surfaces in the development of novel eco-friendly triboelectric nano-generators (LC-TENGs). The composition of lignocellulose and the classification and applications of LC-TENGs are discussed.

Recycling utilization of Chinese medicine herbal residues resources: systematic evaluation on industrializable treatment modes

Traditional Chinese medicine (TCM) is an indispensable part of the world health and medical system and plays an important role in treatment, prevention, and health care. These TCM produce a large amount of Chinese medicine herbal residues (CHMRs) during the application process, most of which are the residues after the decoction or extraction of botanical medicines. These CMHRs contain a large number of unused components, which can be used in medical, breeding, planting, materials, and other industries. Considering the practical application requirements, this paper mainly introduces the low-cost treatment methods of CHMRs, including the extraction of active ingredients, cultivation of edible fungi, and manufacture of feed. These methods not only have low upfront investment, but also have some income in the future. Furthermore, other methods are briefly introduced. In conclusion, this paper can provide a reference for people who need to deal with CMHRs and contribute to the sustainable development of TCM.

Optimization of softwood pretreatment by microwave-assisted deep eutectic solvents at high solids loading

Microwave-assisted deep eutectic solvent (DES) has received attention as an ultrafast pretreatment method in lignocellulose fractionation. This study investigated the improvement of milled softwood mixture (MSM) fractionation with chlorine chloride-formic acid (ChCl:FA) to obtain residues with high glucan retention and purity while removing majority of the lignin and hemicelluloses. At the optimum pretreatment conditions i.e., ChCl:FA (1:4), 140 °C, 14 min, 800 W and 15 % (w/v), 96.2 % hemicellulose removal, 90.1 % delignification and 93.5 % glucan retention were achieved. About 85 % lignin was recovered with a 95 % purity when solid loading was 10-20 % (w/v). This study showed that microwave assisted ChCl:FA pretreatment was a suitable means to fractionate MSM to achieve high quality glucan and lignin at high solid loading.

Applications of biomass-derived solvents in biomass pretreatment - Strategies, challenges, and prospects

Biomass pretreatment is considered a key step in the 2nd generation biofuel production from lignocellulosic biomass. Research on conventional biomass pretreatment solvents has mainly been focused on carbohydrate conversion efficiency, while their hazardousness and/or carbon intensity were not comprehensively considered. Recent sustainability issues request further consideration for eco-friendly and sustainable alternatives like biomass-derived solvents. Carbohydrate and lignin-derived solvents have been proposed and investigated as green alternatives in many biomass processes. In this review, the applications of different types of biomass pretreatment solvents, including organic, ionic liquid, and deep eutectic solvents, are thoroughly discussed. The role of water as a co-solvent in these pretreatment processes is also reviewed. Finally, current research challenges and prospects of utilizing biomass-derived pretreatment solvents for pretreatment are discussed. Given bioethanol's market potential and increasing public awareness about environmental concerns, it will be a priority adopting sustainable and green biomass pretreatment solvents in biorefinery.

Reclamation of ginseng residues using two-stage fermentation and evaluation of their beneficial effects as dietary feed supplements for piglets

Environmental pollution caused by herbal residues, such as ginseng residue (GR), and the huge waste of medicinal ingredients in such residues hinder the development of the pharmaceutical industry. Few studies focused on the biotransformation of GRs and the practical utilization of their bioproducts. In this study, we developed a two-stage fermentation method to optimize GR bioconversion and used the fermented products as dietary supplements for piglets. The tested GR contained abundant lignocelluloses, protein, sugar, and amino acids. Approximately 43.10% of the total lignocelluloses were degraded into sugars by Inonotus obliquus in stage 1 of fermentation. Meanwhile, the sugar content increased by 36.20%, which became the feed for Bacillus subtilis and Saccharomyces cerevisiae in stage 2 of fermentation. These two strains boosted the production of bacterial proteins and other metabolites, including peptides, organic acids, and amino acids. At the end of fermentation, the contents of bioactive compounds significantly increased by 3.18%-21.79%. The dietary supplementation of fermented GR significantly improved the growth performance (6.47%-7.98%), intestinal microbiota, immune function, and healthy status and reduced the diarrhea incidence and noxious gas emission of the piglets. This study provides evidence-based results for the development and deployment of a circular economy between ginseng and livestock industries.

Highly efficient glucose production from raw non-pretreated Chinese medicinal herbal residues via the synergism of cellulase and amylolytic enzymes

Available literature on Chinese medicinal herbal residues (CMHRs) bioconversion highlights pretreatment prior to saccharification with cellulase without considering the presence of starch constituent. Herein, four commonly found CMHRs were tested for starch content, and it was found they all contained starch with content ranging from 4.74% to 16.78%. Hydrolysis of raw CMHRs with combined cellulase and amylolytic enzymes yielded increments of 16.85% to 26.51% in 48-h glucan conversion compared to cellulase alone. Further study showed 48-h glucan conversion of raw CMHRs outperformed that pretreated by water-ethanol successive extraction, ultrasound and acid, but underperformed alkali-pretreated CMHRs. Although increasing 48-h glucan conversion in the range of 7.40% to 24.10% compared to raw CMHRs, alkaline pretreatment demonstrated low glucose recovery and incurred additional cost, making it unfavorable. Saccharification of the four raw CMHRs with combined enzymes seems like a preferred option considering the elimination of high-cost pretreatment step.

Application and prospect of organic acid pretreatment in lignocellulosic biomass separation: A review

As a clean and efficient method of lignocellulosic biomass separation, organic acid pretreatment has attracted extensive research. Hemicellulose or lignin is selectively isolated and the cellulose structure is preserved. Effective fractionation of lignocellulosic biomass is achieved. The separation characteristics of hemicellulose or lignin by different organic acids were summarized. The organic acids of hemicellulose were separated into hydrogen ionized, autocatalytic and α-hydroxy acids according to the separation mechanism. The separation of lignin depends on the dissolution mechanism and spatial effect of organic acids. In addition, the challenges and prospects of organic acid pretreatment were analyzed. The separation of hemicellulose and enzymatic hydrolysis of cellulose were significantly affected by the polycondensation of lignin, which is effectively inhibited by the addition of green additives such as ketones or alcohols. Lignin separation was improved by developing a deep eutectic solvent treatment based on organic acid pretreatment. This work provides support for efficient cleaning of carbohydrate polymers and lignin to promote global carbon neutrality.

Treatment and bioresources utilization of traditional Chinese medicinal herb residues: Recent technological advances and industrial prospect

Traditional Chinese medicine (TCM) has wide application and important functions in curing many diseases, but a great number of herb residues are usually generated after its manufacture and usage. Without proper and timely treatment, these traditional Chinese medicinal herb (TCMH) residues will cause some environmental pollution. In addition to treatment, bioresources utilization of TCMH residues is also important for its great potential as a suitable feedstock for the production of energy, materials, and chemicals. In this situation, advanced and well-designed solid waste management is important to make the TCM industry environmentally friendly and economically attractive. In this review article, the recent progress focusing on various methods for TCMH residues treatment and bioresources utilization are introduced in detail. In particular, the technologies for thermochemical conversion and biochemical conversion of TCMH residues are mainly focused on in order to show how to fulfill effective and efficient bioresources utilization. Besides, some other technologies which are suitable for the treatment and bioresources utilization of TCMH residues are presented as well. Finally, some industrial prospects are given from the economic, operational, and environmental aspects for the further development of treatment and bioresources utilization of TCMH residues. Overall, this work can provide some systematical and comprehensive information for the development of technologies that help sustainably manage the herb residues generated in the TCM industry.

High efficiency and clean separation of eucalyptus components by glycolic acid pretreatment

Glycolic acid has chemical properties similar to those of formic acid. Therefore, similar to formic acid pretreatment, glycolic acid pretreatment has the separation effect of hemicellulose. In this study, eucalyptus hemicellulose was effectively separated by glycolic acid pretreatment. The effects of glycolic acid concentration, temperature and time on the separation of cellulose, hemicellulose and lignin were investigated. The optimum conditions were acid concentration 5.40%, temperature 140 °C, time 3.0 h. The highest yield of xylose was 56.72%. The recovery rate of glycolic acid was 91%. Compared to formic acid, the yield of xylose increased to 10.33% while that of lignin decreased to 11.08%. It showed high selectivity for hemicellulose separation, yielding 65.48% hemicellulose with 72.08% purity. The depolymerization and repolymerization of lignin were inhibited. The integrity of the cellulose structure was preserved. It provides theoretical support for the fractional separation and high-value transformation of lignocellulosic biomass.

Hydrothermal co-hydrolysis of corncob/sugarcane bagasse/Broussonetia papyrifera blends: Kinetics, thermodynamics and fermentation

Biorefinery of biomass blends can achieve sustainable development of biofuel production. Herein, three lignocellulosic wastes with significant differences in chemical composition-namely corncob (CC), sugarcane bagasse (SB), and Broussonetia papyrifera (BP)-were selected to investigate their hydrothermal co-hydrolysis kinetics and thermodynamics of different biomass blends. Activation energies of hemicellulose decomposition (Ea₁, 90.59 kJ/mol) for CC/SB were lower than those for CC (126.12 kJ/mol) and CC/SB/BP (153.62 kJ/mol). BP (having a high content of nitrogen sources) loading weakened the acidic autohydrolysis of CC/SB hemicellulose, but yielded stable products as indicated by the negative entropy value for CC/SB/BP hydrolysis. Cumulative feedback inhibition occurred among different biomass, and it could be minimized by controlling the blending ratio. The highest total xylose yield was 83.64% for CC/SB with a mass ratio of 2:1. Moreover, biomass blend of CC/SB/BP enabled complete utilization of hexose, pentose and amino acids by co-production of ethanol and microalga biomass.

Room temperature dissolving cellulose with a metal salt hydrate-based deep eutectic solvent

Abundant and renewable cellulose is a potential candidate for petroleum-derived synthetic polymers. However, the efficient dissolution of this material is problematic because of the high cost, severe reaction condition (e.g., high temperature) and environmentally unfriendly (e.g., toxic reagents, and solvent recyclability). Herein, to realize the room temperature dissolution of cellulose with an inexpensive and eco-friendly solvent, we design a novel low-cost deep eutectic solvent that is composed of zinc chloride, water and phosphoric acid for the efficient dissolution of cellulose. This solvent is featured as having both the superior hydrogen bonding acidity and the hydrogen bonding basicity, and thus can act as a hydrogen bond molecular scissors to cleave the hydrogen bonds within cellulose. In this process, microcrystalline cellulose can be easily dissolved in the solvent at room temperature with a dissolution ratio up to 15 wt%. The dissolved cellulose can also be recovered without any derivatization. The universality, recyclability and pilot production of dissolving cellulose using this solvent are also demonstrated. This work provides a new strategy for the design of novel deep eutectic solvent capable of disrupting the hydrogen bonds of cellulose under mild conditions.

Using an SGB Decision Tree Approach to Estimate the Properties of CRM Made by Biomass Pretreated with Ionic Liquids

The use of ionic liquids (ILs) for biomass pretreatment to produce cellulose-rich materials (CRMs) has been well proven. In this research, due to the wide range of applications and ease of using artificial intelligence procedures, on the basis of the algorithm of stochastic gradient boosting (SGB) decision tree, an artificial intelligence approach is proposed to estimate the properties of cellulose-rich materials (CRMs). That being the case, the dataset of the empirical output values was gathered and was randomly broken down into datasets for testing and training. These results show that the best forecasting tool for calculating the properties of CRMs is the developed model. Furthermore, the accuracy of the databank of the biodiesel target values has been examined. In contrast, the influences of model contributed variables on the output have been examined as a new issue. It reveals that the most influencing variable in determining the properties of CRMs is the cellulose enrichment factor. Therefore, this research provides an innovative and accurate tool for predicting the properties of CRMs and sensitivity investigation on effective parameters to help investigators developing the optimized process.

Co-production of polysaccharides, ginsenosides and succinic acid from Panax ginseng residue: A typical industrial herbal waste

Co-production of polysaccharides, ginsenosides and succinic acid was achieved from Panax ginseng residue (PGR) in this study. Physico-chemical separation was first applied to recover the released polysaccharides and ginsenoside. Enzymatic hydrolysis was then conducted to covert the left PGR into mono-sugars which was following transformed into succinic acid by constructing a succinic acid-producing strain of Escherichia coli-ZW333. Results indicated that the yields of polysaccharides and ginsenosides increased according to the increase of deconstruction content of PGR. A total sugar yield reached 52 g/L at 10% PGR loading and increased to 94.33 g/L following fed-batch enzymatic hydrolysis. Finally, 56.28 g/L succinic acid was produced. In total, 18 g ginseng polysaccharides, 230 mg ginsenosides and 39 g succinic acid were produced from 100 g PGR. Accordingly, the total economic output could reach RMB 80,149 from 1 t PGR, illustrating the great value increasement of PGR by this industrially possible process.

The Pretreatment of Lignocelluloses With Green Solvent as Biorefinery Preprocess: A Minor Review

Converting agriculture and forestry lignocellulosic residues into high value-added liquid fuels (ethanol, butanol, etc.), chemicals (levulinic acid, furfural, etc.), and materials (aerogel, bioresin, etc.) via a bio-refinery process is an important way to utilize biomass energy resources. However, because of the dense and complex supermolecular structure of lignocelluloses, it is difficult for enzymes and chemical reagents to efficiently depolymerize lignocelluloses. Strikingly, the compact structure of lignocelluloses could be effectively decomposed with a proper pretreatment technology, followed by efficient separation of cellulose, hemicellulose and lignin, which improves the conversion and utilization efficiency of lignocelluloses. Based on a review of traditional pretreatment methods, this study focuses on the discussion of pretreatment process with recyclable and non-toxic/low-toxic green solvents, such as polar aprotic solvents, ionic liquids, and deep eutectic solvents, and provides an outlook of the industrial application prospects of solvent pretreatment.

Catalytic Conversion of Biomass to Furanic Derivatives with Deep Eutectic Solvents

Biomass is the only renewable organic carbon resource in nature, and the transformation of abundant biomass into various chemicals has received immense spotlight. As a novel generation of designer solvents, deep eutectic solvents (DESs) have been widely used in biorefinery due to their excellent properties including low cost, easy preparation, and biodegradability. Although there have been some reports summarizing the performance of DESs for the transformation of biomass into various chemicals, few Reviews illuminate the relationship between the functional structure of DESs and catalytic conversion of biomass. Hence, this Minireview comprehensively summarizes the effects of the types of functional groups in DESs on catalytic conversion of biomass into furanic derivatives, such as carboxylic acid-based hydrogen-bond donors (HBDs), carbohydrate-based HBDs, polyalcohol-based HBDs, amine/amide-based HBDs, spatial structure of HBDs, and various hydrogen-bond acceptors (HBAs). It also further summarizes the effects of adding different additives into the DESs on the synthesis of high value-added chemicals, including water, liquid inorganic acids, Lewis acids, heteropoly acids, and typical solid acids. Moreover, current challenges and prospects for the application of DESs in biomass conversion are provided.

Machine learning prediction of cellulose-rich materials from biomass pretreatment with ionic liquid solvents

Ionic liquid solvents (ILSs) have been effectively utilized in biomass pretreatment to produce cellulose-rich materials (CRMs). Predicting CRM properties and evaluating multi-dimensional relationships in this system are necessary but complicated. In this work, machine learning algorithms were applied to predict CRM properties in terms of cellulose enrichment factor (CEF) and solid recovery (SR), using 23-feature datasets from biomass characteristics, operating conditions, ILSs identities, and catalyst. Random forest algorithm was found to have the highest prediction accuracy with RMSE and R² of 0.22 and 0.94 for CEF, as well as 0.07 and 0.84 for SR, respectively. Highly influential features on making predictions were mainly from biomass characteristics andILS treatment'soperating conditions, totally contributed 80% on CEF and 60% on SR. One- and two-way partial dependence plots were used to explain/interpret the multi-dimensional relationships of the most important features. Our findings could be applied in designing new ILSs and optimizing the process conditions.

A review on the environment-friendly emerging techniques for pretreatment of lignocellulosic biomass: Mechanistic insight and advancements

The process of pretreatment is considered as an indispensable unit operation in the field of lignocellulosic conversion. The traditional pretreatment operations of lignocellulosic biomass are observed as inefficient to meet the demand for an industrial adaptation. In view of that, numerous investigations are reported on various conventional pretreatment methods but very limited information's are available on the advanced technologies. The present review article provides an exclusive discussion on various emerging and environment-friendly pretreatment methods applied on a number of different feedstock materials. Further, an insight on the reaction mechanism involved with each of the technologies such as microwave, ultrasound, deep eutectic solvent, irradiation, and high force assisted pretreatment methods are elucidated for an effective valorization of lignocellulosic biomass. Hence, in a single article, the readers of this paper will get to know all important aspects of the emerging pretreatment techniques of lignocellulosic biomass including the advancements, and the mechanistic insight which will be highly beneficial towards the selection of an efficient pretreatment method for large scale of commercial implementation in a lignocellulosic biorefinery.

Deep Eutectic Solvents as Catalysts for Upgrading Biomass

Deep eutectic solvents (DESs) have emerged as promising green solvents, due to their versatility and properties such as high biodegradability, inexpensiveness, ease of preparation and negligible vapor pressure. Thus, DESs have been used as sustainable media and green catalysts in many chemical processes. On the other hand, lignocellulosic biomass as an abundant source of renewable carbon has received ample interest for the production of biobased chemicals. In this review, the state of the art of the catalytic use of DESs in upgrading the biomass-related substances towards biofuels and value-added chemicals is presented, and the gap in the knowledge is indicated to direct the future research.

The study and application of biomolecules in deep eutectic solvents

Deep eutectic solvents offer stimulating possibilities for biomolecular stabilization and manipulation, biocatalysis, bioextraction, biomass processing, and drug delivery and therapy.

Deep Eutectic Solvent Extraction of High-Purity Lignin from a Corn Stover Hydrolysate

A lactic acid/chlorine chloride-based deep eutectic solvent (DES) was used for the extraction of high-purity lignin (up to 94.7 %) in high yield (up to 75 %) from the hydrolysis/fermentation residue corn stover hydrolysate (CSH), which was generated from a pilot-plant-scale biorefinery. A range of extraction conditions were investigated, which involved varying reaction temperature, time, and DES composition. The relationship between lignin yield, purity, and structural characteristics with DES treatment conditions was determined. The extraction of high-purity lignin from hydrolysis/fermentation residues presents a promising approach for enhancing the economic feasibility of a lignocellulose biorefinery. It was also determined that DES extraction can produce lignin with a controlled range of molecular weight and functional group content.

Integrative transcriptome and proteome analyses provide new insights into different stages of Akebia trifoliata fruit cracking during ripening

BACKGROUND

Akebia trifoliata (Thunb.) Koidz may have applications as a new potential source of biofuels owing to its high seed count, seed oil content, and in-field yields. However, the pericarp of A. trifoliata cracks longitudinally during fruit ripening, which increases the incidence of pests and diseases and can lead to fruit decay and deterioration, resulting in significant losses in yield. Few studies have evaluated the mechanisms underlying A. trifoliata fruit cracking.

RESULTS

In this study, by observing the cell wall structure of the pericarp, we found that the cell wall became thinner and looser and showed substantial breakdown in the pericarp of cracking fruit compared with that in non-cracking fruit. Moreover, integrative analyses of transcriptome and proteome profiles at different stages of fruit ripening demonstrated changes in the expression of various genes and proteins after cracking. Furthermore, the mRNA levels of 20 differentially expressed genes were analyzed, and parallel reaction monitoring analysis of 20 differentially expressed proteins involved in cell wall metabolism was conducted. Among the molecular targets, pectate lyases and pectinesterase, which are involved in pentose and glucuronate interconversion, and β-galactosidase 2, which is involved in galactose metabolism, were significantly upregulated in cracking fruits than in non-cracking fruits. This suggested that they might play crucial roles in A. trifoliata fruit cracking.

CONCLUSIONS

Our findings provided new insights into potential genes influencing the fruit cracking trait in A. trifoliata and established a basis for further research on the breeding of cracking-resistant varieties to increase seed yields for biorefineries.

Different adsorption behaviors and mechanisms of a novel amino-functionalized hydrothermal biochar for hexavalent chromium and pentavalent antimony

A novel amino-functionalized hydrothermal biochar modified with nitric acid and nicotinamide (NMSH) was prepared and applied to remove heavy metal in different systems. The study of batch adsorption found that NMSH had different adsorption behaviors for Cr(VI) and Sb(V), and different concentrations of heavy metal ions exhibited different coadsorption behaviors in mixed system. NMSH had great anti-interference ability to coexisting inorganic ion and humic substance. The maximum adsorption capacity of NMSH was 132.74 mg/g for Cr(VI), and 241.92 mg/g for Sb(V). Moreover, different interfering ions and matter had different effects on adsorption. The mechanism study found that the adsorption mechanism of NMSH involved multiple interactions, and the mechanisms were different. Some O-containing functional groups of NMSH could reduce Cr(VI) to Cr(III), but not Sb(V). NMSH had great removal efficiency and reusability performance, which suggested that NMSH had prospects for practical wastewater treatment.

Deep eutectic solvent for lignocellulosic biomass fractionation and the subsequent conversion to bio-based products - A review

Since the introduction of deep eutectic solvent (DES) in biomass processing field, the efficiency of DES in lignocellulosic biopolymer model compounds' (cellulose, hemicellulose and lignin) solubilisation and conversion was widely recognized. Nevertheless, DES's potential for biorefinery application can be reflected more accurately through their performance in raw lignocellulosic biomass processing rather than model compound conversion. Therefore, this review examines the studies on raw lignocellulosic biomass fractionation using DES and the subsequent conversion of DES-fractionated products into bio-based products. The review stresses on three key parts: performance of varying types of DESs and pretreatment schemes for biopolymer fractionation, properties and conversion of fractionated saccharides as well as DES-extracted lignin. The prospects and challenges of DES implementation in biomass processing will also be discussed. This review provides a front-to-end view on the DES's performance, starting from pretreatment to DES-fractionated products conversion, which would be helpful in devising a comprehensive biomass utilization process.

Enzymatic in situ saccharification of herbal extraction residue by a medicinal herbal-tolerant cellulase

Herbel-tolerant strains exhibit considerable environmental and commercial values not only due to their harmless treatment of herbal-extraction residues (HERs) but also because of their use in preparing high-quality cellulase cocktails. In this study, three typical HERs were evaluated for enzymatic in situ saccharification performance. A HERs-tolerance fungus, identified as Penicillium oxalicum G2, can grow in 1.5% (w/v) Radix isatidis residues (RIR), thereby exhibiting the highest FPase (2.2 U/mL), carboxymethyl cellulase (13.3 U/mL), and β-glucosidase (4.6 U/mL) activities. The most effective production of cellulase cocktail was achieved via orthogonal experiment in a system with pH 6.0, 30 °C, and 96 h. Cellulase cocktail from P. oxalicum G2 can directly saccharify the extraction RIR, thereby achieving a maximum reducing sugar yield of 7.2 mg/mL, which is 1.7-fold higher than those of commercial cellulases. Results illustrate the potential of P. oxalicum G2 for enzymatic in situ saccharification.

In situ deep eutectic solvent pretreatment to improve lignin removal from garden wastes and enhance production of bio-methane and microbial lipids

Biomass pretreatment can improve the conversion efficiency of bioenergy production. Liquid hot water (LHW) pretreatment is a truly green pretreatment due to its zero chemical use, but has the disadvantages of low lignin removal and pseudo-lignin formation. A modified liquid hot water (MLHW) process based on in situ synthesis of deep eutectic solvent (DES) could efficiently improve delignification of Roystonea regia leaves (LR) and leaf sheaths (LSR). LSR was less recalcitrant than LR, and its characteristics of higher porosity (34.8%) and thinner cell walls (5.2 μm) for LSR contributed it higher lignin removal (53.6%) and lower choline chloride (ChCl) consumption (H₂O-ChCl mass ratio of 2:1) than those (44.6% and 1:2) from LR. Moreover, a great improvement of 309.0% in bio-methane yield was achieved for the MLHW-treated LSR. In addition, in situ DES in MLHW had good biocompatibility with cellulase, microalgae, and yeast.

Integration of facile deep eutectic solvents pretreatment for enhanced enzymatic hydrolysis and lignin valorization from industrial xylose residue

In this study, a novel biomass pretreatment process using three kinds of deep eutectic solvents (DESs) was developed to improve saccharification efficiency and lignin valorization. The major components of xylose residue including cellulose and lignin fractions were released, recovered and utilized. Pretreatment with betaine/lactic acid system at 120 °C for 2 h was found to be the optimal conditions with prominently increased enzymatic digestibility (from 55.3% to 96.8%). The efficient conversion was mainly ascribed to the significant delignification efficiency of 81.6% after betaine/lactic acid pretreatment, which caused incompact structure and corrosive surface of treated xylose residue. The recoverable lignin had high purity, low molecular weight (630-2040 g/mol) and polydispersity (1.07-1.76). Based on the comprehensive analysis, the one-pot DESs system provides us a facile and effective approach for whole components valorization of lignocellulosic materials.

Alternatives for Chemical and Biochemical Lignin Valorization: Hot Topics from a Bibliometric Analysis of the Research Published During the 2000–2016 Period

A complete bibliometric analysis of the Scopus database was performed to identify the research trends related to lignin valorization from 2000 to 2016. The results from this analysis revealed an exponentially increasing number of publications and a high relevance of interdisciplinary collaboration. The simultaneous valorization of the three main components of lignocellulosic biomass (cellulose, hemicellulose, and lignin) has been revealed as a key aspect and optimal pretreatment is required for the subsequent lignin valorization. Research covers the determination of the lignin structure, isolation, and characterization; depolymerization by thermal and thermochemical methods; chemical, biochemical and biological conversion of depolymerized lignin; and lignin applications. Most methods for lignin depolymerization are focused on the selective cleavage of the β-O-4 linkage. Although many depolymerization methods have been developed, depolymerization with sodium hydroxide is the dominant process at industrial scale. Oxidative conversion of lignin is the most used method for the chemical lignin upgrading. Lignin uses can be classified according to its structure into lignin-derived aromatic compounds, lignin-derived carbon materials and lignin-derived polymeric materials. There are many advances in all approaches, but lignin-derived polymeric materials appear as a promising option.