Niger Cellulase Research Articles

Saccharification of Different Delignified Sawdust Masses from Various Trees Along the Lagos Lagoon in Nigeria

Sawdust, a major waste product of the forestry industry, is accumulating along the Lagos Lagoon in Lagos, Nigeria, without it being effectively managed. Besides its use in The saccharification of sawdust could contribute to the development of renewable energy sources and feedstock for bioproduct development. The process is, however, not that straightforward as variables such as the type of cellulase enzyme, pretreatment of the cellulose substrate, and optimizing of cellulase to cellulose ratio are a few that need to be optimized for the process to be effective in terms of glucose production.manufacturing sound-absorbing boards to reinforce concrete beams and for energy purposes, its potential as a renewable energy source and feedstock for bio-product development has not yet been realized. Cellulose, a glucose biopolymer and structural component of cellulose can be hydrolyzed by a hydrolytic enzyme known as cellulase. During the process, the enzyme breaks the B-1,4-glucosidic bond, which keeps the glucose units together, and by acting on this bond, numerous glucose units are released. As part of sawdust, the cellulose molecule is not freely available for the degradation action of the cellulase enzyme as it is strongly associated with lignin, which acts as bio-glue, keeping cellulose and hemicellulose together. Delignification is an effective technique that was used to make the sawdust from ten different trees along the Lagos Lagoon in Nigeria more susceptible to saccharification by cellulase isolated from the fungus Aspergillus niger. Delignified and non-delignified sawdust masses between 2 mg and 10 mg were incubated with the A. niger cellulase solution (2 mg.mL-1), whereafter, the amount of sugar produced by the cellulase action was determined. The percentage saccharification of each sawdust material was also linked with the amount of sugar produced during cellulase action. From these investigations was concluded that delignification increased sugar production when almost all the masses of different sawdust materials were degraded. It was also observed that the ratio of sawdust mass to enzyme concentration is an important variable that influences the effectiveness of the saccharification process. The percentage saccharification of the various sawdust materials was also determined, and it indicated that the highest percentage of saccharification was not obtained when the highest amount of sawdust was degraded, producing the highest amount of sugar.

Temperature-related Saccharification of Delignified Sawdust Materials from the Lagos Lagoon in Nigeria

Sawdust, a product of the forest industry is mostly left untreated as solid waste. This phenomenon is well observed along the Lagos Lagoon in Nigeria where hundreds of trees are cut daily by sawmills to deliver wood for mainly the furniture industry. Different types of trees are utilized in this manner and the massive amounts of sawdust produced as a result of these activities are polluting the environment causing health risks for humans and animals. Cellulose, a glucose bio-polymer is a major structural component of sawdust and could be developed as a renewable energy resource should the cellulose be degraded into glucose, a fermentable sugar. This saccharification was done with Aspergillus niger cellulase and to make the cellulose more susceptible for cellulase action the sawdust was delignified with hydrogen peroxide. Both delignified and non-delignified sawdust were treated with the cellulase enzyme at incubation temperatures of 30°C, 40°C, 50°C, and 60°C. Delignification proved to be effective as an increased amount of sugar was released from all delignified sawdust materials relative to the non-delignified materials when saccharified with A. niger cellulase. Most of the materials were degraded at an incubation temperature of 40°C and 50°C and the highest percentage saccharification of 58% was obtained during the degradation of delignifed cellulose from the tree, Ricindendron heudelotti

Upsurge production of cellulase from maize stover under soildstate conditions mediated by Streptomyces enissocaesilis DQ026641

Bioconversion of waste newspaper into fermentable sugars at different temperatures with different Aspergillus niger cellulase concentrationsJ Boitumelo M Sibiya, J Pieter H van Wyk

Production of cellulase by Aspergillus niger through fermentation of spent mushroom substance: Glucose inhibition and elimination approaches

In this study, the best activity of Aspergillus niger cellulase produced from spent mushroom substance (SMS) was 18.82 U/mL, and its enzymatic hydrolysis ability was similar to that of commercial cellulase (120.70 U/g) at the same enzyme loading. Moreover, A. niger cellulase remained stable at pH and temperature ranges of 4.0–8.0 and 40–60 ℃, respectively. Subsequently, the feedback inhibition by glucose on A. niger cellulase was analysed. When the glucose concentration reached 30 g/L, the activation energy of denaturation was 10.69% lower than that of the group with 0 g/L glucose, indicating that 30 g/L of glucose worsened the stability and decreased the activity of the enzyme. However, the kinetic results showed that glucose inhibition of A. niger cellulase was reversible. A. niger cellulase was used in the lactic acid (LA) fermentation of SMS. The activity of A. niger cellulase inhibited by sugars was recovered through sugar consumption by lactic acid bacteria in separate hydrolysis and fermentation, and the final saccharification yield increased from 81.04% to 87.71%. Under simultaneous saccharification and fermentation, the inhibition was avoided because the sugar concentration was < 10 g/L. Therefore, the final LA concentration and productivity were 31.98 g/L and 0.89 g/L/h, respectively.

Synergistic Hydrolysis of Cellulose by a Blend of Cellulase-Mimicking Polymeric Nanoparticle Catalysts.

Enzyme-like catalysts by design have been a long sought-after goal of chemists but difficult to realize due to the challenges in the construction of multifunctionalized active sites with accurately positioned catalytic groups for complex substrates. Hydrolysis of cellulose is a key step in biomass utilization and requires multiple enzymes to work in concert to overcome the difficulty associated with hydrolyzing the recalcitrant substrate. We here report methods to construct synthetic versions of these enzymes through covalent molecular imprinting and strategic postmodification of the imprinted sites. The synthetic catalysts cleave a cellulose chain endolytically at multiple positions or exolytically from the nonreducing end by one or three glucose units at a time, all using the dicarboxylic acid motif found in natural cellulases. By mimicking the endocellulase, exocellulase, and β-glucosidase, the synthetic catalysts hydrolyze cellulose in a synergistic manner, with an activity at 90 °C in pH 6.5 buffer more than doubled that of Aspergillus niger cellulase at pH 5 and 37 °C and 44% of that of a commercial cellulase blend (from Novozyme). As robust cross-linked polymeric nanoparticles, the synthetic catalysts showed little changes in activity after preheating at 90 °C for 3 days and could be reused, maintaining 76% of activity after 10 reaction cycles.

An enhanced fat extraction from Pycnanthus angolensis (African nutmeg) seeds using cellulase from Aspergillus niger strain BC23

A promising extraction method for obtaining fat from Pycnanthus angolensis seeds through Aspergillus niger strain BC23 enzyme pretreatment and particle size reduction is presented in this work. The employed A. niger enzyme was produced from corn bagasse waste material, which served as the only source of carbon. P. angolensis seeds were dried, pulverized and subsequently sieved into two different particle sizes of 1.0 mm and 1.4 mm. This was followed by enzyme pretreatment prior to fat extraction. Results demonstrated that while the peak enzyme activity (121.036 U/mL) occurred on day 4 of fermentation, the maximum cellulase activity could be achieved at 60% saturation of ammonium sulfate purification. Compared with the results of water-treated and untreated seed samples, the fat yield, free fatty acid and iodine values of the enzyme-treated seed samples were considerably higher (P &lt; 0.05). As peroxide value was less in the enzyme-assisted extracted fat, which pointed to a good-quality oil, the decreased refractive index suggested peak unsaturation. Despite considerable differences (P &lt; 0.05) in refractive indices, fat’s specific gravity matched (P &gt; 0.05) when enzyme-treated, water-treated and untreated samples were compared. On the whole, size reduction of P. angolensis seeds pretreated with A. niger cellulase enzyme to improve both fat quality and yield implied it as a useful inventory for confectionary as well as cosmetic industries.

Estimation of solids and biodegraded metabolites in the raw and processed slurry of the two-phase Nisargruna biogas plant

Bioconversion of waste newspaper into fermentable sugars at different temperatures with different Aspergillus niger cellulase concentrationsJ Boitumelo M Sibiya, J Pieter H van Wyk

Production of Glucose 6-Phosphate From a Cellulosic Feedstock in a One Pot Multi-Enzyme Synthesis.

Glucose 6-phosphate is the phosphorylated form of glucose and is used as a reagent in enzymatic assays. Current production occurs via a multi-step chemical synthesis. In this study we established a fully enzymatic route for the synthesis of glucose 6-phosphate from cellulose. As the enzymatic phosphorylation requires ATP as phosphoryl donor, the use of a cofactor regeneration system is required. We evaluated Escherichia coli glucokinase and Saccharomyces cerevisiae hexokinase (HK) for the phosphorylation reaction and Pseudomonas aeruginosa polyphosphate kinase 2 (PPK2) for ATP regeneration. All three enzymes were characterized in terms of temperature and pH optimum and the effects of substrates and products concentrations on enzymatic activities. After optimization of the conditions, we achieved a 85% conversion of glucose into glucose 6-phosphate using the HK/PPK2 activities within a 24 h reaction resulting in 12.56 g/l of glucose 6-phosphate. Finally, we demonstrated the glucose 6-phosphate formation from microcrystalline cellulose in a one-pot reaction comprising Aspergillus niger cellulase for glucose release and HK/PPK2 activities. We achieved a 77% conversion of released glucose into glucose 6-phosphate, however at the expense of a lower glucose 6-phosphate yield of 1.17 g/l. Overall, our study shows an alternative approach for synthesis of glucose 6-phosphate that can be used to valorize biomass derived cellulose.

Lactic acid production from co-fermentation of food waste and spent mushroom substance with Aspergillus niger cellulase

The feasibility of co-fermentation of food waste and spent mushroom substance for lactic acid with Aspergillus niger cellulase replacing commercial cellulase was explored. In this study, Enterococcus mundtii was used in this study because it could utilize hexose and pentose. When the ratio of food waste and spent mushroom substance was 1:2, lactic acid concentration was 39.22 g/L, 39.28% higher than the weighted average of experimental lactic acid concentrations, indicating that the co-fermentation had positive synergistic effects. Results showed 92.62% of sugars of pretreated spent mushroom substance was released by Aspergillus niger cellulase. Moreover, when Aspergillus niger cellulase was added into the lactic acid fermentation system at 24 h, lactic acid concentration reached 48.72 g/L, which was 22.97% higher than that of the control group with commercial cellulase, because of the disappearance of Veillonella and Saccharomycetales with the Aspergillus niger cellulase addition, thus making more substrates converted into lactic acid.

Optimization and statistical modeling of microbial cellulase production using submerged culture

Bioconversion of waste newspaper into fermentable sugars at different temperatures with different Aspergillus niger cellulase concentrations J Boitumelo M Sibiya, J Pieter H van Wyk

Mass Transfer and Reaction in Hydrolysis of Coconut Husk Using Immobilized Enzyme on Chitosan Magnetic Nanoparticle

A more sustainable energy source is needed to fulfill the increasing demand for energy. In Indonesia, biomass waste utilization as biofuel source shows high potential. Coconut husk is a biomass comprised of cellulose and hemicellulose that can converted to reducing sugar through enzymatic hydrolysis and can be further converted into biofuel. However, enzymatic hydrolysis is expensive, as enzyme is soluble and cannot be separated after use. Immobilization is a technique where an enzyme is trapped onto an insoluble inert support material so that the enzyme can be recovered and reused. Chitosan magnetic nanoparticles (CMNP) are used in this experiment as the support as it is cheap and readily available. Since coconut husk is insoluble, mass transfer phenomena remains a major bottleneck in hydrolysis due to limitations in the substrate to enzyme accessibility, especially when the enzyme is immobilized on an insoluble material like CMNP. If only mass transfer resistance is accounted, hydrolysis only occurs on the enzyme particles’ surface. The mass transfer coefficients obtained are 0.0000723, 0.0368, 0.0295 in respect of A. niger cellulase, T. reesei cellulase, and T. longibrachiatum xilanase. Higher coefficients values contribute proportionally to higher yield. If the reaction is assumed to occur uniformly within the spherical immobilized enzyme, then the substrate will diffuse molecularly through the enzyme, where internal mass transfer is no longer negligible. Thiele’s Modulus obtained are 2.197, 0.0368, 0.0795 in respect of A. niger cellulase, T. reseei cellulase, and T. longibrachiatum xilanase. A smaller value in Thiele’s Modulus (ϕ ≤ 1) shows that diffusion occurs at a faster rate than the enzymatic reaction.

Saccharification of Sawdust Masses from the Lagos Lagoon in Nigeria with Aspergillus niger Cellulase

The Lagos Lagoon in Nigeria is extensively polluted with sawdust produced by hundreds of sawmills located on the banks of the lagoon. In order to develop cellulose as a possible resource of bioenergy different masses of various sawdust materials was exposed to the saccharification action by a fungal cellulase source, Aspergillus niger. Five different masses of delignified and non-delignified sawdust materials have been bio-converted with A. niger cellulase into glucose, a fermentable sugar. The amount of sugar released has increased when increasing masses of waste cellulose was degraded although the percentage saccharification shown a decline when increasing masses was degraded. Delignification of sawdust was effective in terms of sugar production during A. niger cellulase catalyzed degradation as the bio-conversion of all delignified materials produced more sugar than the non-delignified materials. The highest amount of sugar was produced from 10 mg of Pterygota macrocarpa sawdust while the highest percentage of saccharification was calculated at 85% during bio-conversion of 2.0 mg of delignified sawdust from P. macrocarpa. Sawdust along the Lagos Lagoon is a major solid waste product that could be developed as a resource of bio-energy if the cellulose component of this material is effectively saccharified.

Saccharification of Sawdust with Aspergillus Niger Cellulase

Accumulated sawdust is a major waste product produced by numerous active sawmills around the Lagos Lagoon in Nigeria. The potential of this wood waste as a resource for bio-product development through the hydrolysis of its cellulose component into glucose, a fermentable sugar is not yet appreciated. Not only is the environment exposed to this organic pollutant but the health of humans is also at risk. The cellulose content of wood sawdust from five different tropical tree species dumped along the Lagos lagoon has been saccharified with cellulase from Aspergillus niger. In order to increase the amount of fermentable sugars released from the cellulose content the various sawdust samples have been delignified with the Kraft process and hydrogen peroxide treatment prior to A. niger cellulase catalyzed degradation at incubation temperatures of 30 0C, 400C, 500C and 600C, respectively. The delignification process was successful by triggering an increase in sugar formation during cellulase catalyze hydrolyses of all waste cellulose materials with different amounts of sugar produced from the various celluloses.

Hydrolysis of sunflower seed meal lignocellulosic fraction by free and immobilized cellulases

Lignocellulosic biomass is widely abundant in nature and recognized aspotential renewable energy source. Its efficient transformation into bio-basedfuels is enabled only after adequate pretreatment, followed by enzymaticsacharification and microbial fermentation. Hereby we present application of twocellulase preparations – from Aspergillus niger and Trichoderma reesei (Celluclast®)in treating sunflower seed meal lignocellulosic fraction (SSMLF). Temperature andpH optimums of two enzymes were determined – 52 °C and pH4.8 for A. nigercellulase and 55 °C and pH4.5 for Celluclast®. At optimized conditions, milledSSMLF was hydrolyzed by both biocatalysts. With A. niger cellulase higher initialreaction rates were accomplished and yield of 70 mM glucose equivalent wasobtained with 6 % (w/v) of enzyme after 6 hours. On the other hand, applicationof Celluclast® led to lower initial reaction rates and yielded 25 mM of glucoseequivalent with 10 % (v/v) of enzyme. To ensure cost-effective application ofA. niger cellulase, the possibility of its immobilization on different supports wasinvestigated. By using porous methacrylate-based carrier with C6 spacer arm andprimary amino groups – LifetechTM ECR8409, preparation with highest activity wasproduced. This preparation was successfully applied in saccharification of SSMLFand showed unchanged catalytic efficiency comparing to free enzyme.

Molecular Structure, vibrational spectra, Molecular Docking and ADMET Study of Cellulose Triacetate II-=SUP=-*-=/SUP=-

People have started to look for alternative sources because of the health problems created by petrochemical products used in all areas of human life and environmental problems that remain intact in nature for years. In this study, molecular structure analysis of cellulose triacetate II (CTA II) molecule, obtained from cellulose II and acetate, was carried out. There is an important relationship between the structure and activity of molecules, so it is very important to determine the geometric structure of a molecule. Therefore, using density functional theory (DFT) the most stable molecular geometries of the cellulose triacetate II monomer (C12H18O9) as well as dimer (C24H36O18), which included intermolecular H-bonding, were calculated. The analogous calculations were carried out for the (CTA-II)2 nano-cluster (C24H34O17), which represents the local structure of CTA-II crystal, and created by binding the two most stable CTA II molecules by covalent bond. Scaled wavenumbers and potential energy distribution of the vibrational modes of CTA monomer and (CTA-II)2 nano-cluster were computed. In order to evaluate the interaction of CTA II with the Aspergillus niger cellulase enzyme,which is an important that is active in cellulose digestion and CTA II, molecular docking studies were carried out. H-binding interactions between CTA II (in monomeric, dimeric and cluster forms) and the active site of the Aspergillus niger cellulase enzyme were shown. Moreover, in silico ADMET prediction study was calculated for CTA-II monomer to predict its druglikeness properties. Keywords: Cellulose triacetate II, Density Function Theory, IR-ATR, cluster for.

Salt-tolerant mechanism of marine Aspergillus niger cellulase cocktail and improvement of its activity

The cellulase cocktail produced by marine Aspergillus niger exhibits a property of salt-tolerance, which is of great potential in cellulose degradation in high salt environment. In order to explain the mechanism on the salt-tolerance of the cellulase cocktail produced by marine A. niger, six cellulase components (AnCel6, AnCel7A, AnCel7B, AnEGL, AnBGL1 and AnBGL2) were obtained by directed expression. Studies on their enzymatic properties revealed that one β-glucosidase (AnBGL2) and one endoglucanase (AnEGL) exhibited an outstanding salt-tolerant property, and one cellobiohydrolase (AnCel7B) exhibited a certain salt-tolerant property. Subsequent study revealed that the salt-tolerant AnEGL and AnCel7B endowed the cellulase cocktail with stronger salt-tolerant property, while the salt-tolerant AnBGL2 had no positive effect. Moreover, after overexpression of AnCel6, AnCel7A, AnCel7B and AnEGL, the activity of cellulase cocktail increased by 80%, 70%, 63% and 68%, respectively. However, the activity of cellulase cocktail was not improved after overexpression of AnBGL1 and AnBGL2. After mixed-strain fermentation with cellobiohydrolase recombinants (cel6a, cel7a and cel7b recombinants) and endoglucanase recombinant (egl recombinant), the the activity of cellulase cocktail increased by 114%, 102% and 91%, respectively.

Exogenous xylanase expression simultaneously with the indigenous cellulase to increase the cellulose hydrolysis efficiency

To eliminate the xylan steric hindrance to lignocellulosic biomass hydrolysis, a xylanase with exoglucanase and endoglucanase activity was expressed simultaneously with the cellulase in Aspergillus niger. The indigenous coding sequence of the endoglucanase in A. niger was replaced by the encoding xylanase sequence by Agrobacterium mediated transformation. The xylanase was transcribed and translated simultaneously with the indigenous exoglucanase and β-glucosidase. The xylanase activity of the reconstructed A. niger was 3.28 U/mL. The activity of the exoglucanase from the constructed strain was increased to 1.95 U/mL from 0.21 U/mL of the original A. niger. The reconstructed A. niger cellulase could hydrolyze wheat straw to release 19.7 g/L of glucose, compared to 12.01 g/L of that released by the cellullase from the original A. niger. More efficient hydrolysis was achieved by the expression of an exogenous xylanase integrated under the expression regulation system of an indigenous endoglucanase in A. niger.

Imobilizacija Aspergillus Niger celulaze na Lifetech TM nosače i primena u reakciji hidrolize lignocelulozne frakcije suncokretove sačme

Cellulases are enzymes which catalyse cellulose hydrolysis and are widely used in various industry branches. Lately, their application in treatment of different agroindustrial waste materials which could serve for fuel production is being extensively explored. In order to increase their stability and cost-effectiveness of their usage, application of their immobilized forms are preferred over free enzymes. Hereby, we tested eight different LifetechTM immobilization supports differing in polarity, porosity and functional groups as carriers for Asspergillus Niger cellulase immobilization. Most promising carrier was methacrylate based, with primary amino groups, C6 "space arm" and pores with diameter of 60-120 nm - LifetechTM ECR8409F. For this support, most important immobilization parameters were investigated and after 3 h at pH 6 with initial protein concentration of 23.3 mg/g support immobilized cellulase with 406 IU/g (with carboxymethyl cellulose as a substrate) was obtained. This preparation was successfully applied in the hydrolysis of lignocellulosic fraction of sunflower seed meal, which is widely available byproduct of sunflower seed meal fractionation for protein-rich fractions production. Initial reaction rates and yields of reducing sugars were unchanged comparing to free enzyme, indicating that there were no significant diffusion limitations for substrate to approach active sites of A. Niger cellulase molecules immobilized onto LifetechTM ECR8409F support.

Immobilization of Aspergillus niger cellulase on multiwall carbon nanotubes for cellulose hydrolysis

In present study, Aspergillus niger cellulase was immobilized onto functionalized multiwalled carbon nanotubes (MWCNTs) via carbodiimide coupling. MWCNTs offer unique advantages including enhanced electronics properties, a large edge to basal plane ratio, rapid electrode kinetics and it’s possess higher tensile strength properties due to their structural arrangements. The immobilization was confirmed by FTIR (Fourier transform infrared spectroscopy) and SEM (scanning electron microscope). The bionanoconjugates prepared under optimized condition retained 85% activity with improved pH and thermal stability. The t1/2 of immobilized cellulase at 70 °C was four fold higher than free enzyme. The Km value indicates that affinity of bionanoconjugates towards substrate has increased by two times. The preparation could be reused ten times without much loss in enzyme activity. The enhanced catalytic efficiency, stability and reusability makes it useful for efficient cellulose hydrolysis.

Comparative analyses of enzymatic activity, structural study and docking of fungal cellulases

Aspergillus cellulase was observed to show superior hydrolysis of microcrystalline cellulose (Avicel PH101) when compared to Trichoderma cellulase. In silico physicochemical characterization revealed the acidic nature of selected fungal cellulases. GRAVY index for Aspergillus and Trichoderma cellulase was −0.314 and −0.374, respectively. Negative values of GRAVY index for both the fungal cellulases indicate that these enzymes have better interaction with water. Secondary structures such as alpha helices (34.44%) and random coils (54.21%) were found to be dominant in A. niger and T. longibrachiatum cellulase, respectively. Validation results for homology modeled 3D structures of selected cellulases indicated their fine quality. The analyses revealed that 96.7 and 92.4% residues of the constructed cellulase models of A. niger and T. longibrachiatum were placed in the favored region, respectively with >82 ERRAT overall quality factor and have >0.7 QMEAN 4 score. ProSA evaluation revealed that the Z-score for A. niger and T. longibrachiatum cellulase was −9.2 and −6.78, respectively. Energy minimization results revealed that the potential energies −7.140×105kJ/mol and −1.228×106kJ/mol were found remaining constant after 744 and 1431 steps for A. niger and T. longibrachiatum cellulases, respectively. Molecular docking study revealed that TRP 200, THR 201 and GLU 160 residues from A. niger cellulase and ASP 220, GLN 196, TYR 192 and TYR 168 residues from T. longibrachiatum cellulase interact with the cellulose. Studies such as this could prove to be helpful in terms of formulating cellulase enzyme for the purpose of industrial use.