High Lignin Research Articles

Fabrication of straw-based graphene aerogels for oil/water separation: the effects of crude fiber fractions in straw.

Benefiting from its abundance, eco-friendliness, and sustainability, crop straw is considered a promising candidate combined with graphene oxide (GO) to fabricate straw-based graphene aerogels (SGAs) for oil/water separation. However, considering the complex composition of straw, the roles played by different crude fibers in straw in the formation of SGAs are still unclear. Herein, wheat straw (WS) was used in this work and pretreated with acid and alkali to regulate its crude fiber fractions. Then, it was crosslinked with GO to fabricate various SGAs for comparing their differences in the formation, structure, and oil/water separation performance. Results indicated that acid can remove plentiful hemicellulose from the WS (from 29.9 ± 2.1 to 7.0 ± 0.8 wt%) while retaining most lignin and cellulose; alkali can retain cellulose (from 32.4 ± 3.6 to 70.6 ± 1.3 wt%) while greatly removing lignin and hemicellulose. Ascribed to high BET surface area and porous structure, the graphene aerogels formed by acid-/alkali-treated WS demonstrated superior oil absorption capacity (AC-WSGA: 62.3-126.0g/g and AL-WSGA: 66.3-125.2g/g). The poor mechanical compressibility of AC-WSGA was caused by the high lignin residue (16.2 ± 0.7 wt%) in AC-WS. The maximum compressive stress for AL-WSGA under 60% strain was 1.6kPa, ensuring it achieved recoverable oil-absorbing properties by extrusion. The above findings suggested that cellulose and hemicellulose in straw contributed to the formation of SGAs with abundant porous and compressible architecture, whereas the presence of lignin greatly increased the brittleness of SGAs and decreased their oil removal and recycling performances.

Catalytic Oxidation of Kraft Lignin in a Trickle-bed Continuous Reactor.

For the first time, the catalytic oxidation of Kraft lignin over a solid heterogeneous catalyst was studied in a continuous lab-scale trickle-bed reactor. This catalytic process is able to depolymerize Kraft lignin and produce phenolic compounds of interest such as vanillin. The impact of operating conditions such as temperature, residence time, contact time, catalyst loading and lignin concentration was evaluated. The formation of vanillin, the main phenolic compound detected in reaction products, was favored at medium temperature (200°C), short contact time (< 1 gcat.min.gfeed-1), high catalyst loading (32 g) and low lignin concentration (5 g.L-1). The vanillin productivity is 30 times higher in a continuous fixed bed reactor than in a batch reactor.

Mechanical, Antimicrobial and Morphological Properties of Biodegradable Trays Based on Cassava Starch and Agroindustrial Processing Residues

ABSTRACTThis study investigated the development of biodegradable composites using agroindustrial residues, such as potato peels and mango integument, processed into flours (PPF and MIF), and determined their nutritional composition, total phenolic content and total tannins. The soluble and insoluble lignin content was quantified in the MIF, which exhibited a high crude fibre content (76.55%) and insoluble lignin (20.86%). Scanning electron microscopy (SEM) examined the morphology of particles and final composites, while the antimicrobial activity of MIF and potato peel extract (PPE) was tested against Staphylococcus aureus. The biodegradability of the composites was assessed in soil, comparing them to commercial EPS. In a factorial design (23), the influence of PPE (1.84–3.68 g), MIF (10–20 g) and drying temperature (55°C–65°C) was investigated regarding the mechanical strength, elongation, antimicrobial activity and physical properties of the composites. Optimal conditions for producing composites with higher strength (1.304 MPa), elongation (0.951%) and antimicrobial activity (30.036‐mm halos) included 3.68 g of PPE, 10 g of MIF and drying at 65°C. However, the interaction between MIF and temperature negatively impacted the results. Biodegradability showed a steady mass loss after 60 days. It is concluded that the use of PPE and MIF offers a sustainable alternative to conventional petroleum‐based packaging, with appropriate production conditions essential to optimize composite properties, reinforcing the potential of the food industry to adopt environmentally friendly materials.

Paralogous Gene Recruitment in Multiple Families Constitutes Genetic Architecture and Robustness of Pod Dehiscence in Legumes.

Pod dehiscence facilitates seed dispersal in wild legumes while indehiscence is a key domestication trait in cultivated ones. However, the evolutionary genetic mechanisms underlying its diversity are largely unclear. In this study, we compared transcriptomes of two warm-season (Glycine spp. and Phaseolus spp.) and two cool-season (Pisum spp. and Medicago ruthenica) legumes in analysis of dehiscent and indehiscent pod genotypes. Differentially expressed genes in AP2/ERF-like transcription factors and seven structural gene families, including lactoperoxidase, laccase, and cellulose synthase-interactive proteins, which are involved in secondary cell wall component accumulation, were identified to exert key roles in pod dehiscence variation. In accordance with this, higher lignin and cellulose contents were observed in pod secondary cell wall of dehiscent accessions of soybean and pea; however, the variation patterns of lignin polymers in soybean (accumulation) and pea (proportion) differed between dehiscent and indehiscent pods. Moreover, genome-wide comparative analysis revealed that orthogroups represented <1% of all identified differentially expressed genes could be traced among the four genera of legumes, while recruiting paralogous members may constitute the genetic robustness of legume pod dehiscence. This study compared the genetic mechanism among several legumes in pod dehiscence formation and revealed a compensating role of paralogous redundancy of involved gene families in seed dispersal, which can guide crop breeding.

Dynamic formation mechanism of persistent free radicals driven by water-phase oxidation-dependent heterogeneity of the carbon−silicon coupling structure in biochar

The formation of persistent free radicals (PFRs) in biochar (BC) is closely related to the structural characteristics and reactivity of BC, which have toxic effects on the environment. However, the mechanisms driving PFRs formation through structural evolution during oxidative aging of BC remain unclear. Herein, we propose a novel dynamic mechanism for BC-PFRs formation driven by oxidation-dependent heterogeneity in carbon−silicon coupling structures by evaluating their heterogeneous correlations, sequential responses, and synergistic relations. The sequential destruction of the “outer carbon−middle silicon−inner carbon” spatial layer and the transformation of molecular components caused by continuous oxidation of BC contributed to the formation of BC-PFRs with two concentration peaks. Moreover, two-dimensional correlation spectroscopy combined with infrared spectroscopy and high-resolution mass spectrometry revealed the sequential responses of carbon−silicon functional groups in BC (Si−O−Si groups → silicon enclosed structures → carbon groups) and BC-derived dissolved organic molecules (lipid-/aliphatic-/carbohydrate-like molecules → lignin-/tannin-like molecules → condensed aromatic molecules), leading to the staged formation of BC-PFRs. High molecular-weight lignin-/tannin-like and condensed aromatic molecules in the carbon layer contributed to BC-PFRs formation, whereas crystalline silicon components hindered the oxidative degradation of inner aromatic carbon and subsequent PFRs formation. Our findings help elucidate potential environmental behaviors and risks associated with BC-PFRs.

High acetone soluble organosolv lignin extraction and its application towards green antifouling and wear-resistant coating

Marine fouling poses significant challenges to the efficiency and longevity of marine engineering equipment. To address this issue, developing effective marine antifouling coatings is critical to ensure the economic viability, environmental sustainability, and safety of offshore operations. In this study, we developed an innovative green antifouling and wear-resistant coating based on lignin, a renewable and sustainable resource. Lignin is considered environmentally friendly because it is abundant, biodegradable, and reduces reliance on petroleum-based materials. The coating was formulated with a controlled hydrophilic-to-hydrophobic ratio of 2:8, leveraging lignin's unique properties. Applying lignin increased the water contact angle by 14.5 %, improving surface hydrophobicity and contributing to the coating's antifouling efficacy. Moreover, the mechanical strength of the coating was enhanced by approximately 200 %, significantly boosting its durability in harsh marine environments. Additionally, the friction coefficient was reduced by about 85 %, further preventing organism adhesion. These results demonstrate that lignin-based coatings offer a greener alternative to traditional antifouling solutions. The results of this study not only help advance antifouling coating technology but are also consistent with the broader goal of promoting environmental responsibility in marine engineering practice.

Controllable preparation of lignin-based photothermal composites based on fractionation treatment

Using natural renewable lignin to prepare new photothermal materials can improve the value of lignin, reduce costs, and promote sustainable development. However, the heterogeneity of lignin is an important factor limiting the stability and tunability of lignin-based photothermal materials. In this paper, lignin after fractionation treatment was blended with the Polybutylene succinate (PBS) to obtain an environmental-friendly, tunable and multifunctional photothermal material. The modulation and enhancement of the compatibility, mechanical, thermal, and photothermal properties of PBS/Lignin composites were achieved by adjusting the structure of lignin. The abundant conjugated structure and high near-infrared (NIR) light absorption capability endowed the high molecular-weight lignin with 71.34 % photothermal conversion efficiency, which led to the maximum surface temperature of the as-prepared composite reached 291 °C under NIR light of 0.9 W/cm2. Meanwhile, the composite exhibited favorable light-triggered shape memory behavior (98.2 % fixation rate and 92.6 % recovery rate), effective light-controlled self-healing capability (91.6 % self-repairing efficiency), and significant photothermal antimicrobial activity (90.6 % inhibition of Escherichia coli, 88.1 % inhibition of Staphylococcus aureus) under the stimulation of NIR light. This study serves as a reference for regulating and enhancing the photothermal conversion efficiency of lignin and developing environmental-friendly photothermal materials.

Unraveling the dynamics of lignin chemistry on decomposition to understand its contribution to soil organic matter accumulation

Abstract Aims Plant inputs are the primary organic carbon source that transforms into soil organic matter (SOM) through microbial processing. One prevailing view is that lignin plays a major role in the accumulation of SOM. This study investigated lignin decomposition using wood from different genotypes of Populus tremula as the model substrate. The genotypes naturally varied in lignin content and composition, resulting in high and low lignin substrates. Methods The wood was inoculated with fresh soil and decomposition was interpreted through mass loss and CO2 produced during a 12-month lab incubation. Detailed information on the decomposition patterns of lignin was obtained by Two-dimensional Nuclear magnetic resonance (2D NMR) spectroscopy on four occasions during the incubations. Results The lignin content per se did not affect the overall decomposition and ~ 60% of the mass was lost in both substrates. In addition, no differences in oxidative enzyme activity could be observed, and the rate of lignin decomposition was similar to that of the carbohydrates. The 2D NMR analysis showed the oxidized syringyl present in the initial samples was the most resistant to degradation among lignin subunits as it followed the order p-hydroxybenzoates &gt; syringyl &gt; guaiacyl &gt; oxidized syringyl. Furthermore, the degradability of β–O–4 linkages in the lignin varied depending on the subunit (syringyl or guaiacyl) it is attached to. Conclusions Our study demonstrates that lignin contains fractions that are easily degradable and can break down alongside carbohydrates. Thus, the initial differences in lignin content per se do not necessarily affect magnitude of SOM accumulation.

Methane Generation Potential of the Easily Degradable Group of Landfilled Municipal Solid Waste

Municipal solid waste (MSW) remains in sanitary landfills for many years. To maintain a circular economy, assessing the feasibility of reinserting MSW excavated from sanitary landfills into the production chain is important. This reduces environmental impacts, helping to minimize soil, water, and air pollution resulting from the decomposition of waste in landfills. In addition, it promotes economic benefits from the energy recovery of waste, such as biomass, which can generate electricity and heat, contributing to a sustainable energy matrix. The present study aimed to evaluate the easily degradable MSW group with 24 years of landfilling (ED-24) regarding its potential for methane generation. The ED group consisted of putrescible organic matter, wood, paper, cardboard, and pruning landfilled at a sanitary landfill in Southeastern Brazil. The feasibility of valuing ED-24 as a substrate for anaerobic digestion was assessed by analyzing its physical, chemical, and biochemical characterization and calculating its theoretical methane yield (TMY). The total volatile solids (TVS) and holo-cellulose contents of ED-24 were 73.45% and 61.39%, respectively, on a dry-weight basis. These values were in the range of those determined for non-landfilled lignocellulosic materials. Thus, 24 years of landfilling partially degraded the anaerobically lignocellulosic materials. The TMY of ED-24 was 233.41 mL CH4/g TVS, indicating a potential to generate methane. Despite the high lignin value, ED-24 can be valued as a substrate for anaerobic digestion.

Electrospun lignin-loaded artificial periosteum for bone regeneration and elimination of bacteria

Recently, the non-negligible role of the periosteum in bone repair has attracted the attention of researchers. In this study, poly(ε-caprolactone) (PCL)/lignin nano-fibrous membranes prepared by electrospinning are proposed as an artificial periosteum. Both in vitro and in vivo studies confirmed that PCL/lignin membranes have a pro-osteogenic effect. This effect was dependent on the lignin concentration, and there was an optimal concentration at which the membrane possessed the highest osteogenesis-potentiating activity among those tested in this study. In addition, the PCL/lignin membranes exhibited promising antibacterial properties against both E. coli and S. aureus, with high lignin concentrations corresponding to high-bactericidal activity. The prepared PCL/lignin membranes displayed promising osteogenic and antibacterial properties. With satisfactory hydrophilicity and mechanical properties, they hold great potential in serving as an artificial periosteum for bone tissue repair. This study provides both theoretical and laboratory evidence for the application of the renewable resource lignin in the repair of the periosteum and bone injuries.

Unraveling latent affinity of strategically designed histidine-rich biosurfactant via tannery waste bio-upcycling in environmentally-relevant lignin removal from pulp and paper industry effluent

Bioremediation of pulp and paper industry (PPI) effluent is hindered due to biorefractory lignin. Herein, we demonstrate a lignin-specific designer biosurfactant with synergistic binding sites for enhanced lignin removal from PPI effluent. The histidine rich-cationic lipoprotein biosurfactant (HR-CLB) was synthesized by Bacillus tropicus using tanning industry solid waste, animal fleshing by de novo substrate-dependent synthesis pathway. Interestingly, the HR-CLB anchored functionalized carbon (HR-CLBAFC) demonstrated a high lignin sequestration capacity of 93.2 mg/g HR-CLBAFC at optimized time, 60 min; pH, 5; temperature, 45 °C; and mass of HR-CLBAFC, 1.0 g. The sequestration was confirmed by HR-SEM, UV–Vis., FT-IR, and WCA analyses. The isotherm studies revealed the involvement of Freundlich isotherm (regression coefficient, R2: 0.988) in regulating lignin sequestration onto HR-CLBAFC with a Freundlich constant (Kf) of 16.46 ((mg/g)(L/mg)1/n). Moreover, the kinetics studies divulged the contribution of the pseudo-second-order kinetic model (R2: 0.992) in regulating the dynamic mechanism of lignin sequestration onto HR-CLBAFC with a rate constant (k2) of 0.00022 g/mg min. Additionally, the thermodynamics studies discovered a positive Gibbs free energy (ΔG: +170 kJ/mol) and entropy (ΔS°: +130 kJ/mol), indicating the involvement of chemical interaction during the sequestration. Furthermore, the mechanistic study confirmed the role of an incomplete valence shell of nitrogen in histidine centers of HR-CLB in regulating electrostatic interaction with lignin molecules during the sequestration process. Subsequently, the HR-CLBAFC applied for lignin sequestration from the real-time PPI effluent demonstrated an outstanding sequestration efficiency (>99.4%), confirming the unequivocal potential of the HR-CLBAFC matrix in lignin sequestration from real-time PPI effluent.

Evaluating the role of feedstock composition and component interactions on biomass gasification

Biomass gasification offers a solution to waste concerns while generating clean energy. This study examines the gasification of pine sawdust (PS), used ground coffee (UGC), and wheat straw (WS) under identical conditions. The compositions of the biomass samples are determined, and the gasification of individual components (hemicellulose, cellulose, and lignin) are conducted to understand the process’ dependency on the biomass characteristics. The results suggest cellulose and cellulose-rich biomass (PS) produces more tar and less hydrogen than lignin and lignin-rich biomass (UGC and WS). High lignin and hemicellulose content leave more char. Gasification of PS, UGC, and WS yields 12.7, 15.7, and 17.2 vol% hydrogen, respectively. Additionally, cellulose, hemicellulose, and lignin gasification yield 10.5, 22.1, and 30.4 vol% hydrogen, respectively. Comparing experimental and theoretical values for the three biomass samples reveals significant differences due to component interactions. Thermogravimetry analysis (TGA) indicates significant degradation interactions between hemicellulose-lignin, cellulose-hemicellulose, and cellulose-lignin. It is concluded that high cellulose content biomass shows more predictable results, while high lignin and hemicellulose biomass increases secondary reactions or interactions, exacerbating predictability. These findings assist in estimating gasification performance for better biomass selection.

Intraspecific variability in plant and soil chemical properties in a common garden plantation of the energy crop Populus.

Optimizing crops for synergistic soil carbon (C) sequestration can enhance CO2 removal in food and bioenergy production systems. Yet, in bioenergy systems, we lack an understanding of how intraspecies variation in plant traits correlates with variation in soil biogeochemistry. This knowledge gap is exacerbated by both the heterogeneity and difficulty of measuring belowground traits. Here, we provide initial observations of C and nutrients in soil and root and stem tissues from a common garden field site of diverse, natural variant, Populus trichocarpa genotypes-established for aboveground biomass-to-biofuels research. Our goal was to explore the value of such field sites for evaluating genotype-specific effects on soil C, which ultimately informs the potential for optimizing bioenergy systems for both aboveground productivity and belowground C storage. To do this, we investigated variation in chemical traits at the scale of individual trees and genotypes and we explored correlations among stem, root, and soil samples. We observed substantial variation in soil chemical properties at the scale of individual trees and specific genotypes. While correlations among elements were observed both within and among sample types (soil, stem, root), above-belowground correlations were generally poor. We did not observe genotype-specific patterns in soil C in the top 10 cm, but we did observe genotype associations with soil acid-base chemistry (soil pH and base cations) and bulk density. Finally, a specific phenotype of interest (high vs low lignin) was unrelated to soil biogeochemistry. Our pilot study supports the usefulness of decade-old, genetically-variable, Populus bioenergy field test plots for understanding plant genotype effects on soil properties. Finally, this study contributes to the advancement of sampling methods and baseline data for Populus systems in the Pacific Northwest, USA. Further species- and region-specific efforts will enhance C predictability across scales in bioenergy systems and, ultimately, accelerate the identification of genotypes that optimize yield and carbon storage.

Liquid absorbent bamboo fiber foams: Towards 100% ligno-cellulosic menstrual absorbent pads

Traditional menstrual absorbent pads typically combine cellulose fiber fluff pulp with non-biodegradable, petroleum-based superabsorbent polymers (SAPs). To eliminate the need for SAPs, this study explores foaming as a method to create a highly porous lignocellulosic fiber network capable of storing large amounts of fluid. Bamboo fibers were chosen due to their high lignin content, which is expected to help maintain the structural integrity of the porous network during liquid absorption and preventing collapse compared to 100% cellulose fibers. The bamboo fiber foams demonstrated remarkable porosity and superior absorbency compared to commercial pads, but they exhibited lower water retention when subjected to compression. Refining the fibers and incorporating microfibrillated cellulose offer promising opportunities to enhance water retention.

Influence of stem and leaf phenotypes, physiological responses and cellular ultrastructure on defoliated sugarcane cultivars

Defoliation is a primary agronomic traits, its variation depends on different plant species or cultivars. The present article assess the leaf morphological responses, oxidative metabolites and enzymatic activities at sheath base of sugarcane cultivars during defoliation stage of plant leaves. The mature leaf sheath of GT47 strongly wrapped to the stem, and no stem was exposed. The upper and lower edges of the immature fusing abscission zone were parallel, and slightly lower browning area (+ 3 to + 7 leaf position). The ROC22 cultivar was monitored highest leaf sheath-based cellulose and lignin content, followed by GT60 and GT47. Peroxidase activity was higher in leaf sheath base edge (ROC22) as compare to other cultivars. The malondialdehyde content was found highest in GT60, followed by ROC22, and GT47. The exo-β-1,4-glucanase/ cellobiohydrolase activity was found highest in the margin of GT47 than lateral and medial axis of ROC22 and GT60. The axis activity increased exponentially, and ROC22 gradually decreased from the periphery of the mid-axis and lower than GT47 and GT60 in the lateral and mid-axis of leaf. In conclusion, the mature leaves are easy to defoliate mainly loose leaf sheaths, large leaf sheath inclination angles, more deformation during the growth period of the abscission zone, early with large cracks, and slow browning process. Leaf sheaths with high fibre and lignin content showed significant hardness and thickness. The sugarcane cultivars showed positive correlation between peroxidase and malondialdehyde content with the browning process at the base of mature leaf sheaths.

Transcription factor PdMYB118 in poplar regulates lignin deposition and xylem differentiation in addition to anthocyanin synthesis through suppressing the expression of PagKNAT2/6b gene

R2R3-MYB transcription factors function as the master regulators of the phenylpropanoid pathway in which both lignin and anthocyanin are produced. In poplar, R2R3-MYB transcription factor PdMYB118 positively regulates anthocyanin production to change leaf color. However, the molecular mechanism by which it controls different branches of the phenylpropanoid pathway still remains poorly understood. Here, we reported that in addition to anthocyanin synthesis, lignin deposition and xylem differentiation were regulated by PdMYB118 through inhibiting PagKNAT2/6b gene expression. The transgenic poplar plants overexpressing PdMYB118 accumulated more xylem, lignin and anthocyanin. Transcriptome and reverse transcription quantitative PCR analyses revealed that the expression of PagKNAT2/6b gene which inhibited lignin deposition and xylem differentiation was significantly down-regulated in transgenic poplar plants. Subsequent dual-luciferase reporter and yeast-one-hybrid assays demonstrated that PdMYB118 directly inhibited the transcription of PagKNAT2/6b by binding to the AC elements in its promoter region. Further experiments with transgenic poplar plants overexpressing PagKNAT2/6b demonstrated that overexpression of PagKNAT2/6b in the PdMYB118 overexpression background rescued lignin accumulation and xylem width to the same level of wild type plants. The findings in this work suggest that PdMYB118 is involved in the lignin deposition and xylem differentiation via modulating the expression of PagKNAT2/6b, and the PdMYB118- PagKNAT2/6b model can be used for the genetic breeding of new woody tree with high lignin production.

Exploring the constituents and thermal characteristics of miscanthus floridulus for biomass composites

Miscanthus floridulus (MF) possesses notable attributes including high photosynthetic efficiency, rapid growth, robust adaptability, and substantial biomass yield. It is widely researched in fields such as genetics, special materials, bioenergy, and ecological protection. However, the research on the addition of MF for biomass composites remains limited due to the absence of comprehensive analysis concerning the composition, internal molecular structure, and properties of MF. A thorough exploration of the fundamental properties of MF has the potential to broaden their advantages and facilitate the advancement of biomass. This investigation delves into the structural characterization and properties of MF, focusing on its stems, leaves, and tassels. Firstly, the primary constituents of MF comprise cellulose, hemicellulose, and lignin. Cellulose predominates in the stem, exhibiting the highest crystallinity, while lignin content peaks in the tassel with the lowest crystallinity. The leaf falls between these extremes in terms of crystallinity. Secondly, carbon and oxygen elements constitute over 95 % of MF's primary components, alongside trace elements like phosphorus and sulfur. Additionally, chemical structure of MF features abundant characteristic functional groups such as hydroxyl, carbonyl, and benzene rings. Studies indicate that samples with low hemicellulose and high lignin content demonstrate superior thermal stability. Consequently, the stem of MF exhibits optimal low-temperature thermal stability, while the tassel excels in high-temperature conditions. Finally, the data highlights a significant influence in the mechanical properties of polylactic acid materials upon the addition of MF. With a 5 % addition of MF, the tensile modulus and flexural strength of the PLA composite reached their optimal values of 933.91 MPa and 55.28±8.77 MPa, respectively. This research establishes a theoretical groundwork for integrating MF into biomass composite materials.

Isolation and Screening of Indigenous Filamentous Fungi Producing Ligninolytic, Cellulolytic and Hemicellulolytic Enzymes from Decomposed Oil Palm Frond

Oil palm frond (OPF) is a palm oil plantation by-product commonly used in animal feeding in Malaysia. The large production, availability, and nutrient content make OPF the best candidate for utilization as animal feed. However, OPF contains high lignin bonds to cellulose and hemicellulose that further limit the digestibility of rumen microbes to produce volatile fatty acids as an energy source for ruminants. This study aims to identify and determine the enzyme activity (ligninolytic, cellulolytic, and hemicellulolytic) of enzymes extracted from filamentous fungi in the pre-treatment of OPF using the solid-state fermentation (SSF) technique. The enzyme extracted from SSF was determined by its enzyme activity (laccase, lignin peroxidase, manganese peroxidase, carboxymethylcellulose, avicelase, and xylanase). Eight fungi were successfully identified to produce enzymes determined in this experiment. Phanerina mellea showed the highest average ligninolytic enzyme activity with a value of 0.37 U/mL and an average cellulolytic + hemicellulolytic of 0.18 U/mL. In this experiment, P. mellea was the most desired fungi for the pre-treatment of OPF. The optimum ligninolytic enzyme production time of OPF pre-treatment is 10 days of SSF.

Investigating the Variation between Lignin Content and the Fracture Characteristics in Capsicum annuum Mutant Stems

The cultivation of horticultural plants in controlled greenhouse environments is a pivotal practice in modern agriculture, offering the potential to enhance crop productivity and mitigate climate change effects. This study investigates the biomechanical properties and lignin content of various Capsicum annuum mutant lines—‘fragile-plant’ (frx), ‘tortuous internodi’ (tti), and ‘puffy-structured stem’ (pfi)—in comparison to a commercially established variety, ‘Garai Fehér’. We employed the acetyl bromide method to quantify lignin content and conducted three-point bending tests to assess rigidity in three distinct regions of the stem. Gene expression analysis of key lignin biosynthetic pathway genes (PAL, C4H, 4CL, CCoAOMT, CAD) was performed using qRT-PCR. The results revealed significant differences in lignin content and breaking force among the genotypes and stem regions. The tti mutants exhibited similar lignin content to the control but lower breaking strength, likely due to elongated internodes. The frx mutants showed uniformly reduced lignin content, correlating with their fragile stems. The pfi mutants displayed abnormally high lignin content in the top region yet demonstrated the lowest stem rigidity in every region. Overexpression of CAD and CCoAOMT was detected in the mutants in specific regions of the stem, suggesting alterations in lignin biosynthesis; however, we could not confirm the correlation between them. Our findings indicate that while lignin content generally correlates with stem rigidity, this trait is complex and influenced by more factors.

Assessment of the chemical composition of buriti (Mauritia flexuosa Liliopsida) and cassava (Manihot esculenta Crantz) residues and their possible application in the bioproduction of coconut aroma (6 pentyl-α-pyrone).

This work aimed to define strategies to increase the bioproduction of 6 pentyl-α-pyrone (bioaroma). As first strategy, fermentations were carried out in the solid state, with agro-industrial residues: Mauritia flexuosa Liliopsida. and Manihot esculenta Crantz in isolation, conducting them with different nutrient solutions having Trichoderma harzianum as a fermenting fungus. Physicochemical characterizations, centesimal composition, lignocellulosic and mineral content and antimicrobial activity were required. Fermentations were conducted under different humidification conditions (water, nutrient solution without additives and nutrient solutions with glucose or sucrose) for 9days. Bioaroma was quantified by gas chromatography, assisted by solid-phase microextraction. The results showed the low production of this compound in fermentations conducted with sweet cassava (around 6ppm (w/w)). The low bioproduction with sweet cassava residues can probably be related to its starch-rich composition, homogeneous substrate, and low concentration of nutrients. Already using buriti, the absence of aroma production was detected. Probably the presence of silicon and high lignin content in buriti minimized the fungal activity, making it difficult to obtain the aroma of interest. Given the characteristics presented by the waste, a new strategy was chosen: mixing waste in a 1:1 ratio. This fermentation resulted in the production of 156.24ppm (w/w) of aroma using the nutrient solution added with glucose. This combination, therefore, promoted more favorable environment for the process, possibly due to the presence of fermentable sugars from sweet cassava and fatty acids from the buriti peel, thus proving the possibility of an increase of around 2500% in the bioproduction of coconut aroma.