Delignification Process Research Articles

“Top-down” fabrication of anisotropic, lightweight, super-amphiphobic, and thermal insulating rattan aerogels

Lightweight and sustainable aerogels have been a growing interest for thermal insulation applications due to current environmental and energy challenges. The design of cellulose-based aerogels with thermal insulation, hydrophobic, and oleophobic performance is the future development direction for building energy-efficient buildings. Herein, an anisotropic, lightweight, super-amphiphobic and thermal insulating rattan aerogel was fabricated by a three-step process of delignification, freeze-drying, and silylation. The prepared rattan aerogel exhibits anisotropic thermal properties with a low thermal conductivity of 0.030 W m–1 K–1 in the radial direction and 0.056 W m–1 K–1 in the axial direction due to the run-through channel skeleton and the structure of the insulating cages. Moreover, the silylated rattan aerogel shows super-amphiphobic performance (water contact angle ∼164° in the cross section and ∼156° in the radial section; oil contact angle ∼158° in the cross section and ∼154° in the radial section). The excellent anisotropic thermal performance, abundance, sustainability, and superb amphiphobicity of the rattan aerogel make it highly promising for green buildings and thermal management applications.

Modification of Orange Bagasse with Reactive Extrusion to Obtain Cellulose-Based Materials

Orange bagasse (OB) could be considered a sustainable, renewable, and low-cost biomass for the extraction of cellulose. In this context, reactive extrusion can be considered an excellent, eco-friendly, alternative process for the extraction of cellulose from lignocellulosic materials. Thus, the present study aimed to obtain cellulose-based materials with a reactive extrusion process and also to investigate the impact of pectin on the delignification process. Two groups of samples (OB and depectinizated OB) were submitted to extrusion with sulfuric acid or sodium hydroxide in one-step processes. The cellulose content of extruded materials was highly affected by pectin content in the raw material; the thermal profile (TGA curves) and crystallinity also changed. The cellulose content of modified materials ranged from 18.8% to 58.4%, with a process yield of 30.6% to 79.2%. The alkaline reagent provided the highest cellulose content among all extrusion treatments tested, mainly for OB without pectin. The extrusion process was considered an efficient and promising process for extracting cellulose from citrus residue. Materials produced in this study can be used as sources of cellulose fiber for various products and processes, such as in the food industry, fermentation substrates, or refined applications after subsequent treatments.

Multifunctional cellulose wood with effective acoustic absorption

Wood is a sustainable material with big sound absorption potential based on its natural porous characteristics. However, the acoustic absorption performance of wood is greatly limited by the low permeability of wood structures. In this study, we prepared a new type of cellulose wood (CW) using a two-step delignification process on a natural basswood matrix followed by supercritical CO2 drying. The as-prepared CW exhibited a high air permeability of 33.78 Darcys (increase of 496.82%) and superior porous characteristics compared to the natural basswood, resulting in a significant improvement in the acoustic absorption performance with an increased average absorption of 106.25% and maximum absorption of 126.32%. The dissipation of sound energy in the structure of CW is well predicted by a designed porous media model. Moreover, a high specific stiffness of 2.14 × 105 m2 s−2 and a diffuse reflectance of 97.02% across the visible light were demonstrated for the CW as well. Such a fascinating multifunctional wood-derived material may provide new insights into the development of efficient and sustainable acoustic absorbers for various applications.

Optimasi Suhu dan Waktu Proses Delignifikasi pada Isolasi Selulosa dari Tongkol Jagung

This study aims to optimize the temperature and time of the delignification process to isolate cellulose from corn cobs. The research was carried out in stages, namely preparing corn cob powder samples and the delignification process. Statistical regression modeling and optimization of the temperature and time of the delignification process used the response surface (RSM) methodology. Central Composite Design (CCD) was used for experimental design and analysis of the effect of temperature and time of the delignification process on lignin, cellulose, hemicellulose, and fiber yields. The optimum process conditions were determined using the desirability method. The analysis of the diversity of the quadratic polynomial model shows that the temperature and time of the deligninification process significantly affect changes in the characteristics of lignin, cellulose, hemicellulose, and fiber yields. The optimal condition of the corncob fiber delignification process was obtained at a temperature of 100.38? for 79.17 minutes. It produced the characteristics of delignified fiber with lignin, cellulose, hemicellulose, and yields of 6.47%, 73.73%, 5, respectively. 39% and 57.76% w/w. The optimization model is valid with a desirability value of 0.71. Thus, the temperature and time optimization model of the delignification process can be applied in real conditions to produce delignified corncob fiber with optimum characteristics.

Structural elucidation and targeted valorization of poplar lignin from the synergistic hydrothermal-deep eutectic solvent pretreatment

Elucidating the structural variations of lignin during the pretreatment is very important for lignin valorization. Herein, poplar wood was pretreated with an integrated process, which was composed of AlCl3-catalyzed hydrothermal pretreatment (HTP, 130–150 °C, 1.0 h) and mild deep-eutectic solvents (DES, 100 °C, 10 min) delignification for recycling lignin fractions. Confocal Raman Microscopy (CRM) was developed to visually monitor the delignification process during the HTP-DES pretreatment. NMR characterizations (2D-HSQC and 31P NMR) and elemental analysis demonstrated that the lignin fractions had undergone the following structural changes, such as dehydration, depolymerization, condensation. Molecular weights (GPC), microstructure (SEM and TEM), and antioxidant activity (DPPH analysis) of the lignins revealed that the DES delignification resulted in homogeneous lignin fragments (1.32 < PDI < 1.58) and facilitated the rapid assemblage of lignin nanoparticles (LNPs) with controllable nanoscale sizes (30–210 nm) and excellent antioxidant activity. These findings will enhance the understanding of structural transformations of the lignin during the integrated process and maximize the lignin valorization in a current biorefinery process.

Lignin removal improves xylooligosaccharides production from poplar by acetic acid hydrolysis

Organic acid hydrolysis is a potential method for xylooligosaccharides (XOS) production from lignocelluloses. However, the effect of lignin content on XOS production using organic acid hydrolysis remains unclear. In this work, the effect of delignification on XOS production from poplar by acetic acid (AC) hydrolysis was investigated. Hydrogen peroxide-acetic acid (HPAC) pretreatment catalyzed by 0–200 mM H2SO4 (HPAC0–HPAC200) removed 21.6–86.5% of lignin in poplar. HPAC pretreatment increased the xylan accessibility to AC solution, thus increasing the xylan removal during AC hydrolysis. An appropriate delignification (61.7%) resulted in the highest XOS yield of 37.4% by AC hydrolysis, increased by 29.9% compared to the optimal XOS yield (28.8%) from raw poplar. After alkaline post-incubation, the glucose yield of poplar residue rose from 57.1% to 78.6%. This work developed a delignification process to efficiently improve XOS and monosaccharides production from poplar.

Delignification of Oil Palm Empty Bunch with Compressive Heat and Naoh Concentration in Separate Lignosellulose

Delignification is a pretreatment in bioethanol processing to separate lignin and cellulose in materials containing lignocellulose such as TKKS. In the delignification process, some lignin will be dissolved. This study aimed to determine the lignocellulosic content in TKKS using the pressurized heat method and the concentration of NaOH. The study was conducted by preparing TKKS samples for alkaline delignification (NaOH) with various concentrations of 10%, 20%, and 30%. Then delignification was carried out using a hot autoclave with an absolute pressure of 4 bar, at a temperature of 120°C for 30 and 60 minutes. The research data were analyzed using Completely Randomized Block Design (CRBD) with the Polynomial Orthogonal follow-up test. The results showed that the cellulose obtained was most abundant at 10% NaOH concentration within 30 minutes, namely 58.33%, and the lowest was at 30% NaOH concentration with 47.3% 60 minutes. Then the highest hemicellulose was found in 10% NaOH concentration with a time of 30 minutes, namely 18.25%, and the lowest was at 30% NaOH with 30 minutes, namely 9.03%. Then the highest Lignin at 10% NaOH concentration with a time of 30 minutes is 10.14%, and the lowest at 30% NaOH concentration with a time of 60 minutes is 3.3%.

Optimization of Delignification Process of Reeds as Raw Materials for Making Art Paper

AbstractArt paper is a handicraft product made from fibers derived from plants. Plants that are used as the basic material for making art paper are plants that contain cellulose. One of plants that can be used as the basis for art paper are reeds. Reeds is one type of grass plant that can grow on land that has moist or dry characteristics. The aim of this research is making best-quality art paper from reed waste in order to tackle the environmental problem aftermath production process in reed drink industry. The laboratory activity of this research was carried out in August 2021 in laboratory of Universitas Brawijaya. For analysis, Design Expert 10 software with Response Surface method was used to get the optimum treatment in the process of delignification of reeds. There were two factors used in the Response Surface method, namely the raw material of reeds is the concentration of acetic acid with 85%, 90%, and 95% and cooking time of 30 minutes, 60 minutes, and 90 minutes. The optimum point of reeds delignification was the treatment with a 92.50% of acetic acid concentration and cooking time of 65.87 minutes which obtained cellulose and lignin of 77.501% and 7.352% respectively.

Strategic lignin removal from lignocellulosic matrix of wheat straw using selectivity characteristics of ozone

Current study was planned to investigate the ozone selectivity for lignin in wheat straw delignification process under controlled conditions. Operating variables such as ozone concentration, reaction time of ozone with wheat straw and flow rate of ozone were explored and the focus was to prevent depolymerization of cellulose in the lignocellulosic matrix. The novelty in the technique is the strategic use of operating parameters to get maximum lignin removal and least cellulose damage in wheat straw matrix. The removal of lignin was maximum till the first 60 minutes for the ozone flowrates of 4 L min-1, 2 L min-1 and 1 L min-1 of reaction. Further increase in reaction time above 60 min made the process less selective. Results support the idea that the lignin can both sustain and restrict the disintegration of carbohydrates. The flow rate of 2L min-1 with a contact time of 60 min is recommended for optimum removal of 85% of lignin.

Hydrostable reconstructed wood with transparency, Excellent ultraviolet-blocking performance, and photothermal conversion ability

Natural wood has been used as building components for thousands of years due to its abundance, high mechanical strength, and durability. However, suboptimal mechanical performance, moisture sensitivity, and inferior optical performance have severely limited its further development and application prospects. Herein, we fabricated a novel full-wood material based on process of delignification, TEMPO-oxidation, in situ lignin deposition, and densification. The resulting reconstructed wood exhibited excellent optical properties, including ultraviolet-blocking, visible-light transparency, and photothermal conversion ability. Moreover, the densified structure integrated the high mechanical strength (high longitudinal tensile strength of 196.8 MPa and Young's modulus of 24.5 GPa) with significantly high resistance to water. The novel concept of reconstructed wood proposed in this study provides new horizons and design guidance for applications in green energy-efficient buildings, photothermal conversion apparatus, decorative materials, and optical devices. • Cellulose scaffold is extracted from wood by delignification/TEMPO-aided oxidation. • Lignin is in situ deposited in cellulose scaffold to fabricate reconstructed wood. • The reconstructed wood exhibits high mechanical strength and good water resistance. • The composites also show UV shielding, transparency, and photothermal conversion.

Insight into the extraction and characterization of cellulose nanocrystals from date pits

This study aims to extract and characterize cellulose nanocrystals (CNCs) from date pits (DP), an agricultural solid waste. Two methods were used and optimized for the cellulose nanocrystals (CNCs) extraction, namely the mechanical stirrer method (CNCs 1 ) and the Soxhlet apparatus method (CNCs 2 ) in terms of chemical used, cost, and energy consumption. The results showed that scanning electron microscopy revealed the difference in the morphology as they exhibit rough surfaces with irregular morphologies due to the strong chemical treatments during the delignification and bleaching process. Moreover, transmission electron microscopy analysis for CNCs reveals the true modification that was made through sulfuric acid hydrolysis as it presents cellulose microfibrils with a packed structure. Fourier transform infrared proved that the CNCs were successfully extracted using the two methods since most of the lignin and hemicellulose components were removed. The crystallinity index of CNCs 1 and CNCs 2 was 69.99%, and 67.79%, respectively, and both presented a high yield of CNCs (≥10%). Ultimately, both techniques were successful at extracting CNCs. Based on their cost-effectiveness and time consumption, it was concluded that method 1 was less expensive than method 2 based on the breakdown of the cost of each step for CNCs production.

Chemical and enzymatic deinking efficiency of agricultural and industrial waste fiber-based paper packaging.

Deinking is an important part of paper recycling that involves the removal of ink particles from the paper fibres. This industrial process is important so that the fibres can be recirculated back into paper production, which enables better sustainability as fewer fresh fibres are needed. In this study, we examined five different alternative fibre materials from different agricultural residues and industrial processes for the pilot production of papers. Papers containing fibres from invasive plants (Japanese knotweed), dedicated crops (miscanthus, acacia), agricultural residues (tomato stems), and industrial waste (jute - fibres from coffee bags) were printed with water-based flexo inks and deinked with two separate processes (chemical and enzymes). Mechanical (break and tensile index, breaking length) and optical properties (ISO whiteness, brightness and CIE L*a*b* values) were measured and ink elimination IR700 and deinking efficiency was calculated for the two deinking processes. Enzymatic treatment improved the mechanical properties of deinked pulp in comparison with the classic chemical treatment. Mechanical strength for almost all papers increased slightly (breaking length up to 20% in tomato and jute), and the optical result (brightness) increased similarly for both processes due to the bleaching action of the colour-shaded samples, whereas the deinking efficiency showed mixed results between chemical- and enzyme-type deinking (with chemical achieving better elimination measured at 700 nm) in the typical range of ink elimination values (15-35%) for flexographic inks. This indicates further optimization of the deinking with enzymes is needed due to different alternative fibre compositions and variations of residues in the delignification processes. Using a combination of adjusted enzymatic treatment as a precursor for deinking of paper-based packaging materials sourced from alternative fibres showed promising results regarding mechanical properties, whereas the optical properties need to be improved with cellulase optimization or by using mixes of different enzymes. These kinds of paper materials printed with flexo inks were found to be successfully deinkable with the chemical ISO-based deinking protocol. © 2022 Society of Chemical Industry.

Isolation of White Rot Fungi from Rotten Wood from Bogor Botanical Garden in Indonesia and its Ligninolytic Enzymes Activity

Background: White rot fungus is one of the microorganisms that can naturally decompose lignocellulosic biomass. Indonesia's nature with its tropical forests has enormous potential for the development of white rot fungi that can be used as biological resources, one of which is in the bio delignification process. This paper aims to study the isolation and qualitative and quantitative screening of ligninolytic enzymes from white rot fungi found on rotten wood. Methods: In this study, white rot fungus was isolated from rotten wood from Bogor Botanical Gardens area, Indonesia. The isolated fungus were screened qualitatively by the Bavendamm test and decolorization of Remazol Brilliant Blue R test. Furthermore, the activity of laccase enzymes, manganese peroxidase and lignin peroxidase were measured by UV-Vis Spectroscopy. Laccase enzyme as an enzyme that has the highest activity is produced in liquid media containing rice husks and purified and its activity is measured. Result: The results showed that of the 5 isolates that were positive for Bavendamm test and decolorization of RBBR test, they were KRB1, KRB8, KRB9, KRB10 and KRB12. The highest laccase activity was produced by isolates KRB 12 at 8244.72 U/ml. Laccase was purified by precipitation of ammonium sulfate at a saturation level of 0-80%. Laccase was precipitated optimally in ammonium sulfate saturation 0-20%. The overall yield of the purification was 44.92%, with a purification fold of 1.72 and a specific activity of 5579.95 U/mg protein. Conclusion: The result for isolate KRB12 laccase as compared of the reported laccases suggests isolate KRB12 is a potential isolate for the production of laccase enzymes. Key words: White rot fungi, Isolation, Bavendamm test, Decolorization of RBRR, Laccase, Manganese peroxidase, Lignin peroxidase.

Role of Combined Na2HPO4 and ZnCl2 in the Unprecedented Catalysis of the Sequential Pretreatment of Sustainable Agricultural and Agro-Industrial Wastes in Boosting Bioethanol Production.

Improper lignocellulosic waste disposal causes severe environmental pollution and health damage. Corn Stover (CS), agricultural, and aseptic packaging, Tetra Pak (TP) cartons, agro-industrial, are two examples of sustainable wastes that are rich in carbohydrate materials and may be used to produce valuable by-products. In addition, attempts were made to enhance cellulose fractionation and improve enzymatic saccharification. In this regard, these two wastes were efficiently employed as substrates for bioethanol production. This research demonstrates the effect of disodium hydrogen phosphate (Na2HPO4) and zinc chloride (ZnCl2) (NZ) as a new catalyst on the development of the sequential pretreatment strategy in the noticeable enzymatic hydrolysis. Physico-chemical changes of the native and the pretreated sustainable wastes were evaluated by compositional analysis, scanning electron microscopy (SEM), X-ray diffractometry (XRD), Fourier transform infrared spectroscopy (FTIR), and thermogravimetric analysis (TGA). These investigations showed major structural changes after the optimized sequential pretreatment. This pretreatment not only influences the delignification process, but also affects the functionalization of cellulose chemical structure. NZ released a higher glucose concentration (328.8 and 996.8 mg/dl) than that of ZnCl2 (Z), which released 203.8 and 846.8 mg/dl from CS and TP, respectively. This work led to the production of about 500 mg/dl of ethanol, which is promising and a competitor to other studies. These findings contribute to increasing the versatility in the reuse of agricultural and agro-industrial wastes to promote interaction areas of pollution prevention, industrialization, and clean energy production, to attain the keys of sustainable development goals.

The Delignification of Plants Residue Substrate and Accelerated Fungal Consortium Growth-Saccharification: A Practical Approach

The environments have created an abundance of residual plants from all life sectors, which is not optimal for bioethanol. Therefore, this research developed microbial technology that yielded sugar and fermentation testing. The research aimed to discover the delignification process and compare the consuming sugar by Saccharomyces cerevisiae between the chemical saccharification and accelerated bio-agent of fungal consortium in the engineered media. The innovation of the bioethanol process was conducted using raw materials from biomass. Based on this study, some preliminary hypotheses were made: (i) arranging fungal substrate which consists of residual sugar, molasses, and enriched residual papaya fruits could provide distinguishable growth of cell mass; (ii) the substrate concentration of 2.5% and 7.5% in the growth medium using enriched residual papaya fruits, respectively, as a medium, could be distinguished using delignification. A benchmark was used to compare the chemical and bio-agent saccharification. The consortium that grew and produced cell mass by times factor in molasses has fulfilled the element needed compared to the natural organic substances from the papaya fruit. The higher concentration of delignification material substrate yielded higher growth-saccharification and the average of 10.45 ± 0.21 % Brix was obtained by the fungal consortium in the broth medium, although the acceleration growth is insignificant. Nonetheless, Saccharomyces cerevisiae had successfully fermented saccharification yield sugar from the delignification of plants residual

The Utilization of Oil Palm Empty Fruit Bunches for Growth of Oyster Mushroom (Pleurotus ostreatus) and Biodelignification Process During Planting Cycle

Indonesia produces a large amount of oil palm empty fruit bunch (EFB) that has potency used as media for mushroom cultivation. The research emphasized the use of EFB to grow oyster mushrooms as an alternative for delignification without chemicals. This research aimed to study the growth of oyster mushroom (Pleurotus ostreatus) at EFB based growing media treatments. The media consisted of a mixture of EFB and sawdust at the composition of 0%, 25%, 50%, 75%, and 100%. The media were also supplemented with rice bran, CaCO3, and TSP fertilizer. The data were collected on the mycelium growth and the mushroom weight. During cultivation in baglog, there was no difference in mycelium growth rate. The EFB composition of 25% showed faster growth among the other compositions, followed by the EFB composition of 50%, 75%, and 0%. The highest Biological Efficiency Ratio (BER) at 56.25% was obtained at media composition of 50%. The EFB contained in baglog also showed biodelignification process. Biodelignification has the benefit which can reduce the use of chemicals in the delignification process to convert EFB into cellulose. The highest lignin reduction (40.12%) occurred in 75% of EFB media composition, while hemicellulose (49.56%) occurred in 100% EFB media composition.

Wood Veneer Reinforced with Bacterial Cellulose: Tensile Strength and Dynamic Mechanical Analysis

Cellulose from plants is a natural polymer that is very abundant, cheap and easy to process. In addition, there is bacterial cellulose produced from bacterial fermentation of acetic acid with limited production but has high purity, crystallinity, and tensile strength. In this research, the process of wood-veneer delignification was carried out to self-assembly bacterial cellulose into wood cavities on bacterial culture media. Wood veneer reinforced bacteria cellulose was given heat pressure to increase the density and it was expected to form hydrogen bonds between their cellulose molecular chains. This study observed the duration of fermentation in bacterial media culture on the tensile strength of hybrid veneers, microscopic observations, the effect of water on set-recovery, and the characteristics of solid veneers on cyclic loading and temperature using dynamic mechanical analysis (DMA) testing. The microscopic observations prove that Acetobacter xylinum can penetrate the veneer and assemble bacterial cellulose in the cavity. A higher tensile strength ratio of 81.38% was observed in densified veneers with a five-day fermentation period with a modulus of elasticity 156.63% higher than natural veneers. The minimum set-recovery after boiling the hybrid veneer was 29.32%. DMA showed that by reinforcing wood veneer with bacterial cellulose and compacting, it increased cyclic energy storage ability, reduced energy loss, and increased stability under increasing temperatures. Strengthening wood with bacterial cellulose in this method opens new potential for developing more environmentally friendly forest products in the future.

High strength holocellulose paper from bamboo as biodegradable packaging tape

As the fast-growing of package business in express delivery industry, replacing traditional scotch tapes with degradable materials has attracted extensive attention. Herein, holocellulose paper (H-paper) was prepared by an efficient delignification and papermaking process from bamboo. The structure and properties of resultant holocellulose fibers and H-paper were characterized and compared with those from other pulping methods, such as Kraft pulping, enzyme treated, sulfite and alkaline sulfite process. The yield of holocellulose pulp (55%) increased by about 10% compared with that of other fibers. Compared to that of Kraft paper (38 MPa), the strength of H-paper increased by nearly 60% at similar density, reaching a maximum of 65 MPa. The total transmittance of H-paper was about 20% higher than Kraft paper. Moreover, H-papers displayed high mechanical properties, good printability, and degradability, which was important for the application as paper tape.

Delignification of hemp stalk using a low transition temperature mixture composed of choline chloride and lactic acid

This work used a literature search to select the most suitable system for the delignification process of annual plants. This process was evaluated in terms of lignin removal from plant biomass. Based on previous experiments, a low transition temperature mixture (LTTM) was used, which was a mixture of choline chloride and lactic acid in a molar ratio of 1:2. Samples of hemp fibers were examined. The delignification of biomass was monitored by changing the content of the main components. After application of the solvent at a temperature of 100, 120, or 140 °C and a delignification time of 2 or 4 h, the lignin content expressed by Kappa number decreased to the level of 22 to 13.7. Yields of hemp fibers sown after LTTM application ranged from 72.5 to 90.6%. The results confirmed that the use of LTTM (choline chloride/lactic acid) is a suitable system for the extraction of lignin from biomass. The findings showed that LTTM was an effective delignifying agent for hemp, as a relatively low Kappa number of 13.7 and a yield of 75.9% were achieved after only 2 h and at 140 °C.

The effect of natural fiber (banana fiber) on the mechanical properties of self-compacting concrete

Self-compacting concrete is an innovative concrete technology with higher flowability properties by adding the mineral admixtures such as superplasticizers and not necessary to vibrate concrete. The banana fibers were used in this investigation because banana fiber is an environmentally friendly material with good properties compared to synthetic fiber. The experimental test consisted of two phases of research, i.e., preliminary research, which had the aim to investigate the appropriate percentage of superplasticizer in the mixed composition of self-compacting concrete. The percentages of superplasticizers were 0.7%, 1%, and 1.4%. The second phase of research on the effect of additional banana fiber on self-compacting concrete was carried out, examining workability, compressive strength, and the splitting tensile strength of concrete. In this research, the percentages of fiber were 0.12%, 0.3%, and 0.5% of the cement weight, and evaluated the effect of fiber treatment. The treated fibers mean that the fiber is immersed in NaOH solution or named as a delignification process. The hardened concrete specimen was used for determining the mechanical strengths, such as the compressive strength and split tensile strength tests. The test results found that the optimum value for superplasticizer dosage was 0.7% of cement weight, which can fulfill the whole criteria of fresh concrete and hardened SCC concrete. Furthermore, the specimen with the adding banana fiber of 0.12% by cement weight and treated fiber indicated a decrease in workability. Compared to the control concrete, it inversely increased compressive strength up to 44.36% and tensile strength up to 17.78%.