Fractionation and characterization of lignin from waste rice straw: Biomass surface chemical composition analysis

Unraveling the structural aspects of microwave-assisted OrganoCat-based coconut shell lignins: An eco-friendly route for obtaining bio-based antioxidants

New routes for biomass valorization have been developing by the scientific community. The aim of this work was developing a novel OrganoCat-based protocol and deeply understand the structure of the obtained lignins. Microwave-assisted OrganoCat-based process was performed using a biphasic system (ethyl acetate and oxalic acid or HCl) at mild conditions. OrganoCat-based lignins (OCLs) were characterized by compositional analysis, FTIR, 1H, 13C, 1H13C HSQC, 31P NMR, TGA and GPC. The solubility of OCLs in different organic solvents and their antioxidant capacity against DPPH were investigated. The spectroscopic analyses showed that OCLs have high residual extractives and the lignin motifs were preserved. OCLs have presented lower thermal stability than MWL, but showed great antioxidant activities and high solubility in a wide range of organic solvents. A novel biorefinery protocol yielded coconut shell lignins with peculiar structural and compositional features and several technological applications through an eco-friendly, sustainable and relatively low-cost biphasic pulping process.

Renewing the potential of rice crop residues as value-added products in the cosmetics industry

Purpose of this study is to explore the extraction of potentially valuable cosmetic ingredients from rice crop residues, aiming to mitigate their environmental impact.

Methods

We employed AOAC methods to analyze the fat, protein, ash, fiber, soluble, and insoluble carbohydrate content in these residues. To identify sugars rich in galactose and acidic sugars, a total soluble carbohydrate extraction was performed. Cellulose, as part of the insoluble carbohydrates, was isolated through alkaline and acid hydrolysis, while sodium silicate was derived from the ash. Characterization of insoluble cellulose and silicate involved techniques like FTIR, DSC, PXRD, microphotography, porosity assessments, and water absorption studies. For proteins, alkaline solubilization and precipitation at the isoelectric point were utilized, with quantification via BCA and amino acid profiling through gas chromatography. Evaluation of radical scavenging capacity using DPPH led to the calculation of apparent molecular weight via SDS-PAGE.

Results

The results revealed low levels of gum, mucilage, and pectin in both residues, contrasting with a high concentration of insoluble polysaccharides. Among these, Iβ cellulose displayed potential attributes for cosmetic applications due to its oil and water adsorption characteristics. However, silicates obtained from the ashes did not exhibit direct use potential. In terms of protein extraction, we observed antioxidant properties, with enhanced performance through enzymatic hydrolysis, achieving a hydrolysis degree of 30.41% and a DPPH radical absorption rate exceeding 70%.

Conclusion

Rice residues, particularly husk and straw, shown valuable substances suitable for potential cosmetic applications, encompassing cellulose, hydrolyzed proteins, and ash as a silicate precursor.

Sustainable process for fractionation of lignin by the microwave-assisted chemical additive approach: Towards sugarcane leaf biorefinery and characterization

The microwave assisted pretreatment on sugarcane leaf (SCL) biomass for delignification was studied to enhance cellulose digestibility. In this work, microwave assisted with additives were used to delignification SCL for maximize sugar yield recovery. Single factorial and Central composite design (CCD) were employed to optimize the microwave assisted pretreatment conditions for improve delignification efficiency and the sugar yield recovery. The optimized pretreatment conditions were determined to be 4 min pre-treatment time, 500 W microwave power, 1.0 M Na2CO3 and 10 % biomass loading condition produce maximum reducing sugar yield (601 mg g-1) and glucose sugar yield (231 mg g-1) were achieved during saccharification. Pretreated biomass produced reducing sugar and glucose yields that were 4.5 and 4.1 times higher than those of untreated (native) SCL-N biomass, respectively. Additionally, the recyclability study of black liquor, obtained from optimized conditioned treatment of SCL-MSC (Microwave-assisted sodium carbonate pretreated SCL) resulted in considerable saccharification yield up to three pretreatment cycles. The 1H NMR and 13C NMR spectra studies illustrate that aromatic units present in SCL fractionated lignin samples. The variations of structure features and chemical compositions of the raw and pretreated SCL biomass were analyzed by SEM, XRD and XPS analysis. Overall, SCL-MSC pretreatment condition significantly delignification of SCL and led to the maximum sugar production optimized strategies pretreatment conditions was produced maximum amount of sugar, which is great potential for bio-refinery product development.

Catalytic valorization of Kraft lignin into feedstock chemicals with methyltrioxorhenium (MTO) catalyst in microbial electrochemical cell

In this study, the authors investigate a novel approach to valorize Kraft lignin using the catalyst Methyltrioxorhenium (MTO) in tandem with in-situ produced H2O2 in a Microbial Electrochemical Cell (MEC). This study demonstrates the in-situ oxidation of Kraft lignin using different concentrations of MTO catalyst (2 mM to 8 mM) and H2O2 (5.24 ± 0.40 mM to 8.91 ± 0.70 mM) in three MECs. The depolymerized Kraft lignin samples were characterized using FTIR, CHNS/O, and 1H NMR analysis. The MTO/H2O2 combination showed high selectivity towards the oxidation of Kraft lignin, resulting in both aromatic ring and side chain cleavage reactions and the production of valuable feedstock chemicals. The oxidation also led to a reduction of 68.42 % to 78.18 % in Chemical Oxygen Demand (COD) of lignin. The selective oxidation favored the recovery of Guaiacyl (G) unit-derived feedstock chemicals, with Guaiacol being the most abundant compound (45.04 mg/mL) among the quantified products by HPLC. Additionally, the system demonstrated high efficiency in anodic wastewater treatment, achieving BOD and COD removal rates ranging from 67.68 % to 72.55 %. This method showcases the use of a sustainable system in combination with a selective catalyst to produce valuable products from usually discarded Kraft lignin while simultaneously treating wastewater.

Effects of straw addition on the physicochemical and microbial features of black soldier fly larvae frass derived from fish meat and bone meal

Black soldier fly larvae (BSFL) hold great promise for sustainable management of meat and bone meal (MBM), a kind of organic waste. Harvested BSFL frass can be used as soil amendment or organic fertilizer. This study evaluated the quality and microbial profile in the frass of BSFL, fed with fish MBM containing 0% (CK), 1% (T1), 2% (T2) and 3% (T3) of rice straw. Results suggested straw addition into fish MBM had no significant impacts on BSFL weight; however, straw addition remarkably affected waste reduction and conversion efficiency, as well as physicochemical properties including electric conductivity, organic matter (OM) and total phosphorus contents in frass. Fourier transform infrared analysis indicated that increasing levels of cellulose and lignin might not be fully degraded or transformed by BSFL when more straw was introduced into substrates. Straw addition had hardly significant influences on microbial richness or evenness in BSFL frass, only T3 treatment remarkably elevated the phylogenetic diversity value more than the control. Bacteroidetes, Proteobacteria, Actinobacteria and Firmicutes were the most dominant phyla. Genera Myroides, Acinetobacter and Paenochrobactrum maintained high abundances in all frass samples. Elements including OM, pH and Na were key factors in shaping the microbiological characteristics of BSFL frass. Our findings helped to understand the effects of fish MBM waste manipulation on BSFL frass qualities and contributed to the further application of BSFL frass.

Bioethanol production from alkali-pretreated rice straw: effects on fermentation yield, structural characterization, and ethanol analysis

Current ethanol production technology has a dire need for efficient conversion of lignocellulosic biomass to fermentable sugars. The conversion requires pretreatment of the biomass, one of the most expensive steps, and thus it is quite necessary to identify the most cost-effective and high-efficiency conversion method. In this study, rice straw (RS) biomass was pretreated using 4% NaOH alkali, soaked for 4 h, and autoclaved for 30 min. The structural and morphological changes were examined using Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and scanning electron microscopy (SEM) analysis in both native and alkali-treated RS. The FTIR analysis revealed that native RS contains a considerable amount of lignin that was removed after the pretreatment process. The XRD pattern of the RS revealed an increasing crystallite size of the pretreated lignocellulosic biomass. The study of SEM clearly showed the distorted structure and surface porosity after the pretreatment process. Enzymatic hydrolysis efficiency was checked by comparing the commercial enzymes and microbial hydrolysis extracted from a fungal isolate. The best-reducing sugar yield obtained was 0.62 g/L, achieved at optimized conditions from the commercial enzymes. Fermentation efficiency was checked using the yeast isolate Saccharomyces cerevisiae in both the native and pretreated substrate, and the highest ethanol concentration (21.45%) was achieved using 20% w/v biomass loading, enzyme loading (2:1:1), and fermentation for a week at 30°C and pH 4.5. This concentration was higher than that of the untreated RS (3.67%). The ethanol thus produced was further checked for analysis by the 1H and 13C nuclear magnetic resonance (NMR) methods.

Simultaneous achievement of efficient hemicellulose separation and inhibition of lignin repolymerization using pyruvic acid treatment

The efficiency of organic acid treatment in the conversion of lignocellulosic biomass fractions has been widely recognized. In this study, a novel green pyruvic acid (PA) treatment is proposed. The higher separation efficiency of eucalyptus hemicellulose was obtained at 4.0% PA and 150 °C. The hemicellulose separation yield was increased from 71.71 to 88.09% compared to glycolic acid (GA) treatment. In addition, the treatment time was significantly reduced from 180 to 40 min. The proportion of cellulose in the solid increased after PA treatment. However, the accompanying separation of lignin was not effectively controlled. Fortunately, a six-membered ring structure was formed on the diol structure of the lignin β-O-4 side chain. Fewer lignin-condensed structures were observed. High-value lignin rich in phenol hydroxyl groups were obtained. It provides a green path for the simultaneous achievement of efficient hemicellulose separation and inhibition of lignin repolymerization using organic acid treatment.

Lignin from Brewers' Spent Grain: Structural and Thermal Evaluations

Lignocellulose is a renewable ubiquitous material that comprises cellulose, hemicellulose, and lignin. Lignin has been isolated from different lignocellulosic biomass via chemical treatments, but there has been little or no investigation carried out on the processing of lignin from brewers' spent grain (BSG) to the best of authors' knowledge. This material makes up 85% of the brewery industry's byproducts. Its high moisture content hastens its deterioration, which has posed a huge challenge to its preservation and transportation; this eventually causes environmental pollution. One of the methods of solving this environmental menace is the extraction of lignin as a precursor for carbon fiber production from this waste. This study considers the viability of sourcing lignin from BSG with the use of acid solutions at 100 °C. Structural and thermal analyses were carried out on extracted samples, and the results were compared with other biomass-soured lignin to assess the proficiency of this isolation technique. Wet BSG sourced from Nigeria Breweries (NB), Lagos, was washed and sun-dried for 7 days. Tetraoxosulphate (VI) (H₂SO₄), hydrochloric (HCl), and acetic acid, each of 10 M, were individually reacted with dried BSG at 100 °C for 3 h and designated as H2, HC, and AC lignin. The residue (lignin) was washed and dried for analysis. Wavenumber shift values from Fourier transform infrared spectroscopy (FTIR) show that intra- and intermolecular OH interactions in H2 lignin are the strongest and possess the highest magnitude of hydrogen-bond enthalpy (5.73 kCal/mol). The thermogravimetric analysis (TGA) results show that a higher lignin yield can be achieved when it is isolated from BSG, as 82.9, 79.3, and 70.2% were realized for H2, HC, and AC lignin. The highest size of ordered domains (0.0299 nm) displayed by H2 lignin from X-ray diffraction (XRD) informs that it has the greatest potential of forming nanofibers via electrospinning. The enthalpy of reaction values of 133.3, 126.6, and 114.1 J/g recorded for H2, HC, and AC lignin, respectively, from differential scanning calorimetry (DSC) results affirm that H2 lignin is the most thermally stable with the highest glass transition temperature (T_g = 107 °C).

Removal of As(III) using a microorganism sustained secrete laccase-straw oxidation system

While laccase oxidation is a novel and promising method for treating arsenite-containing wastewater, the high cost and unsustainability of commercially available enzymes indicate a need to investigate more cost-effective viable alternatives. Here, a microorganism sustained secrete laccase-straw oxidation system (MLOS) was established and subsequently evaluated for the removal of As(III). MLOS showed efficient biological As(III) oxidation, with an As(III) removal efficiency reaching 99.9% at an initial As(III) concentration of 1.0 mg·L^-1. IC-AFS and XPS analysis showed that As(III) was partially oxidized to As(V), and partially As(III) adsorbed on the surface of rice straw. FTIR analysis revealed that hydroxyl, amine and amide groups were all involved in the As(III) removal process. SEM-EDS demonstrated that the surface structure of rice straw was destroyed following Comamonas testosteroni FJ17 (C. testosteroni FJ17) treatment, and the metal ions binding sites of rice straw were increased resulting in elemental arsenic being detected on the material surface. Molecular docking revealed the interaction between key residues of laccase and As(III). Laccase activity was negatively correlated with Cu(II) concentration in the As(III) oxidation. EEM showed that humic-like acids were also involved in the interaction with As(III). Overall, a MLOS derived from biomass waste has a significant potential to be developed as a green and sustainable technology for the treatment of wastewater containing As(III).

Exploring the Oxidative Effects of the Microbial Electro-Fenton Process on the Depolymerization of Lignin Extracted from Rice Straw in a Bio-Electrochemical System Coupled with Wastewater Treatment

Lignin is a potential renewable feedstock to produce value-added compounds, but the overwhelming bulk of it is either burned for energy or discarded as waste. This paper addressed two critical issues: waste-to-value generation and management by demonstrating the in situ depolymerization of lignin extracted from waste rice straw utilizing the microbial electro-Fenton process in a microbial peroxide-producing cell (MPPC), a type of bio-electrochemical cell, for value addition while synchronously treating wastewater. The MPPC electrochemical voltage yields of 0.171 ± 0.05-0.497 ± 0.2 V produced 9 ± 0.43-34 ± 0.11 mM of H₂O₂, which was utilized to depolymerize lignin at various concentrations. Interestingly, a direct correlation was observed between lignin depolymerization and H₂O₂ concentration, while Fourier-transform infrared spectroscopy data revealed a constant disruption of the lignin structure accurately in the wavenumber region of 1000-1750 cm^-1 irrespective of the H₂O₂ concentration. Carboxylic acid derivatives, benzopyran, hexanoic acid, and other valuable compounds were detected in the LC QTOF MS data from the depolymerized lignin mixture. Remarkably, SEM analysis demonstrated morphological changes in depolymerized lignin induced by the oxidative effects of hydroxyl radicals. Biochemical oxygen demand and chemical oxygen demand removal was 60 ± 3-85 ± 1% in anodic wastewater treatment. This research provides a sustainable and efficient technique for lignin valorization and wastewater treatment.

Microwave-assisted alkali pre-treatment medium for fractionation of rice straw and catalytic conversion to value-added 5-hydroxymethyl furfural and lignin production

In the current study, the use of microwave-assisted sodium hydroxide medium (MWSH) for pre-treatment and saccharification of rice straw to obtain sugar syrup for the production of 5-hydroxymethyl furfural (5-HMF) was investigated. The optimization of the MWSH pre-treatment was carried out using central composite methodology, resulting in a maximum reducing sugar yield of 350 mg/g of treated rice straw (TRS) and a glucose yield of 255 mg/g of TRS under the conditions of a microwave power of 681 W, a NaOH concentration of 0.54 M, and a pre-treatment time of 3 min. Additionally, the microwave assisted transformation of sugar syrup with titanium magnetic silica nanoparticle as catalyst, producing 41.1 % yield of 5-HMF from the sugar syrup after 30 min microwave irradiation at 120 °C with catalyst loading of 2.0:200 (w/v)). The structural characterization of the lignin was analysed using ¹H NMR techniques, and the surface carbon (C1s spectra) and oxygen (O1s spectra) composition changes of the rice straw during pre-treatment were analysed using X-ray photoelectron spectroscopy. The rice straw based bio-refinery process which contains MWSH pretreatment followed by dehydration of sugars achieved high efficiency of 5-HMF production.

Journey of lignin from a roadblock to bridge for lignocellulose biorefineries: A comprehensive review

The grave concerns arisen as a result of environmental pollution and diminishing fossil fuel reserves in the 21st century have shifted the focus on the use of sustainable and environment friendly alternative resources. Lignocellulosic biomass constituted by cellulose, hemicellulose and lignin is an abundantly available natural bioresource. Lignin, a natural biopolymer has over the years gained much importance as a high value material with commercial importance. The present review provides an in-depth knowledge on the journey of lignin from being considered a roadblock to a bridge connecting diverse industries with widescale applications. The successful valorization of lignin for the production of bio-based platform chemicals and fuels has been the subject of intensive investigation. A deeper understanding of lignin characteristics and factors governing the biomass conversion into valuable products can support improved biomass consumption. The components of lignocellulosic biomass might be totally transformed into a variety of value-added products with the improvements in bioprocess techniques that valorize lignin. In this review, the recent advances in the lignin extraction and depolymerization methods that may help in achieving the cost-economics of the bioprocess are summarized and compared. The industrial potential of lignin-derived products such as aromatics, biopolymers, biofuels and agrochemicals are also outlined. Additionally, assessment of the recent research trends in lignin valorization into value-added chemicals has been done and present scenario of technological-industrial applications of lignin with economic perspectives is highlighted.

Towards integrated sustainable biofuel and chemical production: An application of banana pseudostem ash in the production of biodiesel and recovery of lignin from bamboo leaves

This study investigated an integrated approach to the biowaste transformation and valorization of byproducts. Biochar obtained from the banana pseudostem was calcined to synthesize a heterogeneous catalyst and sustainably prepare a highly alkaline solution. The ash was utilized directly as a heterogeneous catalyst in biodiesel production from waste cooking oil. At the same time, an alkaline solution prepared from the ash was used for delignification and recovery of lignin from bamboo leaves by the hydrothermal reaction. Techniques like Fourier-transform infrared spectroscopy (FTIR), Field emission scanning electron microscopy (FESEM), Brunauer-Emmett-Teller (BET), Transmission electron microscopy (TEM), and Energy dispersive X-ray (EDX) were applied to characterized the catalyst. The alkaline solution was analyzed with Atomic absorption spectroscopy (AAS). The Response surface methodology (RSM) technique was considered for the optimization of different parameters in the transesterification and hydrothermal reaction. Under the optimized condition, waste cooking oil (WCO) to Fatty acid methyl ester (FAME) conversion was 97.56 ± 0.11%, and lignin recovery was 43.20 ± 0.45%. While at the best operating pyrolysis temperature, the liquid fraction yield from the banana pseudostem (500 °C) was 38.10 ± 0.31 wt%. This integrated study approach encourages the inexpensive, sustainable, and environment-friendly pathway for synthesizing catalysts and preparing a highly alkaline solution for the valorization of biowaste into biofuel and biochemicals.

Characteristics of calcium lignin from pulping waste liquor and application for the treatment middle-stage wastewater of paper making

In order to obtain a lignin-based adsorbent with low cost, simple operation and no further modification, a calcium lignin adsorbent was prepared from chemical mechanical pulping (CMP) waste liquor by directly calcification from lime. The calcium lignin was characterized by BET, SEM, TEM, FT-IR and solid-state NMR analyses. The results showed that the molecular structure of the calcium lignin particles did not change when compared to sodium lignin, the formation mechanism of calcium lignin was revealed. The initial COD and lignin contents of CMP waste liquid were 54858 mg/L and 24.39 g/L, the conversion rate of lignin can reach 71.36% when was deal with lime. Thus, most of the lignin resources in the waste liquid were recovered. The middle-stage wastewater (MSWW) of pulping and papermaking was dealt with calcium lignin, the COD removal rate was up to 85.83%. The adsorption isotherms and kinetics were well fitted by the Langmuir model and pseudo-second-order kinetic model, respectively. Lime was regenerated from the used calcium lignin with high-temperature calcination, the conversion rate of calcium ions can reach 83.56%. Overall, the calcium lignin prepared by the one-step method exhibited great potential for effectively removing COD from middle-stage wastewater.

Superior separation of hemicellulose-derived sugars from eucalyptus with tropic acid pretreatment

Organic acid pretreatments can efficiently separate biomass-based hemicellulose and selectively produce hemicellulose-derived sugars. In this study, hemicellulose is separation as xylose, oligosaccharides in the tropic acid-catalyzed hydrothermal pretreatment of eucalyptus. The maximum yield of hemicellulose-derived sugars (85.78 %) with 71.25 % xylose selectivity (based on the total xylose in raw material) was achieved in the hydrolysate under optimal conditions (5 % TA, 160 ℃, 80 min). The yield of hemicellulose-derived sugar and the separation yield of hemicellulose increased by 11.06 % and 11.45 % compared with glycolic acid pretreatment in the similar severity factor. The separation yield of cellulose and lignin was decreased by 4.23 % and 0.98 %, respectively. This resulted in residual solids with higher biological stability (higher fiber crystallinity index, higher thermal stability, and higher lignin content). Therefore, higher hemicellulose separation selectivity and rich hemicellulose-derived sugars were obtained using TA pretreatment. The work would bring up a new method for biomass refining.

Effect of alkaline and deep eutectic solvents pretreatments on the recovery of lignin with antioxidant activity from grape stalks

Grape stalks are lignocellulosic residues that can be valorized through the extraction of lignin - an underutilized biopolymer with high potential. Two lignin extraction methods, alkaline and deep eutectic solvents (DES), were studied, and experimental designs were carried out to obtain the best extraction conditions. The defined parameters for alkaline extraction allowed the recovery of ~48 % of lignin with low purity that was further improved with an autohydrolysis pretreatment (~79 % purity; ~32 % yield). Optimum parameters of DES method rendered high purity lignin (~90 %) without the need of a pretreatment and with a better yield (50.2 % (±2.3)) than the alkaline method. Both lignin fractions presented high antioxidant activities, being close to the antioxidant capacity of BHT for DPPH scavenging. Structural analysis proved the presence of lignin in both alkaline and DES samples with similar morphology. Overall, DES method was more efficient in the extraction of lignin from grape stalks besides its greener and sustainable nature. This work is uses DES to extract lignin from this biomass while comparing it with a commonly classical method, proving that grape stalks can be used to extract lignin with a sustainable and efficient method rendering a final ingredient with value-added properties.

Sustainable Approaches to Selective Conversion of Cellulose Into 5-Hydroxymethylfurfural Promoted by Heterogeneous Acid Catalysts: A Review

5-Hydroxymethylfurfural (5-HMF) as a triply catalytic product is a value-added refining chemical in industry production. 5-HMF as biomass feedstock enables to be transformed into other high-value industrial compounds, such as 2,5-furandicarboxylic acid (FDCA), 5-hydroxymethyl-2-furancarboxylic acid (HMFCA), 5-formyl-2-furancarboxylic acid (FFCA), 2,5-diformylfuran (DFF), 2,5-bis(aminomethyl)furan (BAMF), and 2,5-dimethylfuran (DMF). Hence, catalytic conversion of biomass into 5-HMF has been given much more attention by chemists. In this review, some latest studies about the conversion of cellulose to 5-HMF have been introduced systematically. Solid acids such as heterogeneous catalysts have been widely applied in the conversion of cellulose into 5-HMF. Therefore, some novel solid acids with Brønsted and/or Lewis acidic sites, such as sulfonated solid acids, carbon-based acids, and zeolite particles employed for biomass conversions are listed.

Effect of temperature on simultaneous separation and extraction of hemicellulose using p-toluenesulfonic acid treatment at atmospheric pressure

Hemicelluloses were effectively separated using p-toluenesulfonic acid (p-TsOH) treatment at high temperature. High temperature and pressure promoted hydrolysis of hemicellulose, which limited its value upon recovery. In this study, bagasse hemicellulose was separated and extracted by p-TsOH treatment at atmospheric pressure. The effects of temperature, p-TsOH concentration, and time on hemicellulose separation and extraction were investigated. The optimal conditions were 80 °C, 3.0% p-TsOH, and 120 min. The separation and extraction yield of hemicellulose was 73.23% and 36.02%, respectively. Extraction hemicellulose with 95.60% purity was obtained. In addition, the dissolution mechanism of hemicellulose was analyzed. Degradation of β-glycosidic bonds was inhibited. Benzyl ether bond between carbohydrates and lignin was selectively cleaved. The skeleton structure of xylan in hemicellulose was protected while the functional groups of branch chain were severely damaged. It provides a valuable theoretical basis for the efficient separation and extraction of hemicellulose.

Efficient vanillin biosynthesis by recombinant lignin-degrading bacterium Arthrobacter sp. C2 and its environmental profile via life cycle assessment

Vanillin is a natural flavoring agent that is widely used in the bioengineering industry. To enable sustainable development, joint consideration of bacterial performance and negative environmental impacts are critical to vanillin biosynthesis. In this study, a cold shock protein (csp) gene was upregulated for maintaining stable growth in Arthrobacter sp. C2 responding to vanillin and cold stress. Furthermore, the recombinant strain C2 was constructed by simultaneously deleting the xylC gene encoding benzaldehyde dehydrase and overexpressing the pchF gene encoding vanillyl alcohol oxidase and achieved a maximum vanillin productivity of 0.85 mg/g DCW/h with alkaline lignin as the substrate. Finally, this process generated an environmental impact value of 25.05, which was the lowest environmental impact achieved according to life cycle assessment (LCA). Improvement strategies included reducing electricity consumption and replacing chemicals. This study achieved the development of an effective strategy, and future studies should focus on precise vanillin biosynthesis methods for large-scale application.

Mitigating the Health Effects of Aqueous Cr(VI) with Iron-Modified Biochar

A large amount of chromium (Cr) has entered the natural environment from the wastewater and waste residues, and the hexavalent (Cr(VI)) is highly poisonous, threatening the ecological environment and human health directly. In this study, iron-modified biochar was prepared using honeysuckle residue as raw material and the ferric chloride impregnation method. Batch Cr(VI) adsorption experiments were carried out using the modified honeysuckle-derived biochar (MHDB) as an adsorbent. The results indicate that a pH of 2 was best for the adsorption removal of Cr(VI) in the initial pH range of 2-10. The adsorption kinetic data fitted the pseudo-second-order model best out of the two models, and the Langmuir model was better than the Freundlich model to describe the adsorption process. Thermodynamic analysis indicated that the adsorption process of Cr(VI) on MHDB had an endothermic and spontaneous nature, and the increasing temperature was conducive to the adsorption. The main mechanisms of Cr(VI) adsorption might be the physical adsorption (electrostatic interactions) and chemical adsorption (ion exchange, the reduction of Cr(VI) to Cr(III)). The efficient adsorption of Cr(VI) makes MHDB a potential material for Cr(VI)-containing wastewater treatment. This study provides a feasible adsorption material for mitigating the environmental hazards of chromium, which has a certain reference value for protecting environmental health.

Recent advances in commercial biorefineries for lignocellulosic ethanol production: Current status, challenges and future perspectives

Cellulosic ethanol production has received global attention to use as transportation fuels with gasoline blending virtue of carbon benefits and decarbonization. However, due to changing feedstock composition, natural resistance, and a lack of cost-effective pretreatment and downstream processing, contemporary cellulosic ethanol biorefineries are facing major sustainability issues. As a result, we've outlined the global status of present cellulosic ethanol facilities, as well as main roadblocks and technical challenges for sustainable and commercial cellulosic ethanol production. Additionally, the article highlights the technical and non-technical barriers, various R&D advancements in biomass pretreatment, enzymatic hydrolysis, fermentation strategies that have been deliberated for low-cost sustainable fuel ethanol. Moreover, selection of a low-cost efficient pretreatment method, process simulation, unit integration, state-of-the-art in one pot saccharification and fermentation, system microbiology/ genetic engineering for robust strain development, and comprehensive techno-economic analysis are all major bottlenecks that must be considered for long-term ethanol production in the transportation sector.

Ammonia Fiber Expansion Combined with White Rot Fungi to Treat Lignocellulose for Cultivation of Mushrooms

In order to improve the degradation efficiency of lignocellulose while increasing the yield of mushrooms, white rot fungi treatment (Pleurotus ostreatus, Pleurotus eryngii, and Pleurotus geesteranus) combined with ammonia fiber expansion was proposed as a method for treating lignocellulose (Pennisetum sinese, salix chips, and pine chips) for mushroom cultivation. Compared with treatment using either ammonia fiber expansion or white rot fungus, the combined treatment significantly improved lignocellulose degradation rate by 10-20% and reduced the time required significantly. Among them, P. geesteranus was the most effective bacterium for the combined treatment of lignocellulose. Ammonia fiber expansion-treated lignocellulose contributed to mycelial growth and increased the activity of three lignin hydrolase enzymes (laccase, manganese peroxidase, and lignin peroxidase) and mushroom yield. The mushroom yield was increased by 44.6%. The combined treatment method proposed in our study improves lignocellulose resource utilization and is therefore useful in the treatment of agricultural solid organic waste.

Lignin from Morinda citrifolia leaves: Physical and chemical characterization, in vitro evaluation of antioxidant, cytotoxic, antiparasitic and ultrastructural activities

In this work, we investigated in vitro the antioxidant, cytotoxic and anti-leishmanial activities of a lignin extracted from the leaves of Morinda citrifolia. Initially, an analysis of the composition of the sheets was performed, then the lignin was obtained by alkaline delignification and characterized by different techniques: elemental analysis, FT-R, UV-vis, HSQC-NMR, thermal analysis, Py-GC/MS and by GPC. The results showed that the leaves had in their composition cellulose (31.29%), hemicellulose (25.01%), lignin (18.34%), extractives (14.39%) and ash (10.03%). The lignin extraction yield was 89.8%. The lignin obtained is of the GSH type with the following contents 79.39%, 13.58% and 7.03% respectively. Furthermore, it is low molecular weight and thermally stable. It had a phenolic content of 93.3 mg GAE/g and low antioxidant activity. In macrophage cytotoxicity assays, it presented a CC₅₀ of 31.0 μg/mL, showing less toxicity than amphotericin B. In assays against the promastigote forms of Leishmania amazonensis, lignin presented an IC₅₀ of 29.56 μg/mL, a less effective concentration than amphotericin B (IC₅₀ = 0.14 μg/mL). However, it was able to promote inhibition of the parasites, a fact confirmed by structural changes. These findings reinforce that M. citrifolia lignin is a promising macromolecule for use as an antiparasitic and antioxidant agent.

Fractionation, characterization, and economic evaluation of alkali lignin from saw industry waste

The present work was focused on the investigation of lignin isolation from saw industry biomass (sawdust (SD)) using alkali solution, and to perform economic analysis for 2000 kg/batch hypothetical plant using techno-economic analysis. The isolated lignin was fractionated using organic solvent to obtain purified lignin. FTIR and ¹H NMR analysis were performed to examine the structural characteristics of lignin. Lignin nanoparticles (LN) showed higher total phenolic content (TPC) (244.1 ± 2 µg of GAE per mg) and antioxidant activity (63.2 ± 1.7%) compared with crude lignin (CL), ethanol fractionated lignin (EL), and acetone fractionated lignin (AL). SuperPro designer was exposed to design and simulated 2000 kg/batch of sawdust fractionation process. The techno-economic analysis estimated that the lignin production cost is about $ 487,000 per year, and the annual revenue could be $ 1,850,000 per year. The techno-economic analysis and sensitivity analysis could be useful for the industrial level sawdust fractionation process.

Recent progress in the conversion of biomass wastes into functional materials for value-added applications

The amount of biomass wastes is rapidly increasing, which leads to numerous disposal problems and governance issues. Thus, the recycling and reuse of biomass wastes into value-added applications have attracted more and more attention. This paper reviews the research on biomass waste utilization and biomass wastes derived functional materials in last five years. The recent research interests mainly focus on the following three aspects: (1) extraction of natural polymers from biomass wastes, (2) reuse of biomass wastes, and (3) preparation of carbon-based materials as novel adsorbents, catalyst carriers, electrode materials, and functional composites. Various biomass wastes have been collected from agricultural and forestry wastes, animal wastes, industrial wastes and municipal solid wastes as raw materials with low cost; however, future studies are required to evaluate the quality and safety of biomass wastes derived products and develop highly feasible and cost-effective methods for the conversion of biomass wastes to enable the industrial scale production.