| HS Code | 260983 |
| Product Name | Grass Raw Material Pulping Enzymes |
| Enzyme Type | Cellulase and Xylanase Complex |
| Appearance | Light yellow to brown powder or liquid |
| Odor | Slight fermentation odor |
| Solubility | Completely soluble in water |
| Optimum Temperature | 50-60°C |
| Optimum Ph | 4.5-6.0 |
| Enzyme Activity | ≥100,000 U/mL |
| Dosage | 0.1-0.5% of dry grass material weight |
| Storage | Keep in cool, dry, and ventilated place |
| Shelf Life | 12 months from date of manufacture |
| Packaging | 25 kg fiber drum or 25 L plastic drum |
| Safety | Non-toxic and biodegradable |
As an accredited Grass Raw Material Pulping Enzymes factory, we enforce strict quality protocols—every batch undergoes rigorous testing to ensure consistent efficacy and safety standards.
| Packing | Grass Raw Material Pulping Enzymes are packed in 25 kg sealed drums with inner plastic bags, moisture-proof and safe for transport. |
| Container Loading (20′ FCL) | 20′ FCL loading of Grass Raw Material Pulping Enzymes: palletized drums, secured, ventilated, moisture-proof, safe for transport. |
| Shipping | Grass Raw Material Pulping Enzymes ship as non-hazardous liquid or powder in sealed drums or IBCs. Keep cool, dry, and ventilated; avoid extreme temperatures and direct sunlight. Standard freight or refrigerated transport is suitable, with proper labeling and documentation to prevent contamination and maintain enzyme activity. |
| Storage | Store Grass Raw Material Pulping Enzymes in original, tightly sealed containers in a cool, dry, well-ventilated area, away from direct sunlight and heat sources. Recommended storage at 2–8°C (refrigerated) to maintain enzyme activity; avoid freezing. Protect from moisture and contamination. Follow FIFO rotation and check expiry dates. Keep separate from incompatible materials. Always refer to the Safety Data Sheet for specific instructions. |
| Shelf Life | Shelf life is typically 6–12 months when stored cool, dry, and protected from direct sunlight. |
In mills running continuous screw feeders above 12 t/h on air-dried wheat straw, the rate-limiting step is not alkali diffusion but gel hydration of soluble arabinoxylans in the defibering zone. Chopped straw with node content above 6% w/w produces erratic screw torque and non-uniform impregnation. An enzyme premix containing endoxylanase and pectate lyase is dosed at 0.5–1.5 kg/t OD straw into the pre-steaming vessel at 55–60 °C and 8.5–9.5 pH for 40–50 min, ahead of caustic addition. The pectate lyase cleaves pectic acid in the middle lamella after methyl ester saponification, while xylanase reduces alkali-soluble hemicellulose gel viscosity. Subsequent cooking in a continuous tube digester with 10–12 g/L NaOH at 160–170 °C reaches a kappa number near 60–70. Refining on a 12-inch double-disc refiner is adjusted to 420–450 mL CSF measured by ISO 5267-1, because lower freeness raises ring crush but collapses bulk and slows corrugator take-up. The resulting fluting medium is conditioned per ISO 187 and tested for ring crush according to ISO 12192; values above 1.8 N·m/g are typically required for lightweight corrugated board. Operation above 0.30% w/w OD enzyme addition is not recommended, since excess cellulase background activity in some technical blends reduces viscosity and yield by 2–3 percentage points and increases fines in white water. Batch-to-batch variance in straw pectin content between 2.5% and 5.5% w/w shifts the optimum dose by ±0.10 percentage points, and the dose must be trimmed weekly against screw press amperage and drainage tests.
The first measurable constraint appears in the brown stock washing stage, where dissolved sodium silicate raises filtrate viscosity and deposits scale on evaporator tubes. Rice straw with silica content above 40 g/kg dry matter requires a combined acid-chelation and enzymatic pre-bleaching protocol. Washed pulp is treated with EDTA or DTPA at 0.2–0.3% w/w OD, pH 5.5–6.5, 50 °C for 30 min, then transferred to an enzyme tower where family 11 endoxylanase is dosed at 0.05–0.10% w/w OD pulp, pH 7.5–8.5, 50–60 °C, retention 45–90 min. The enzyme releases hemicellulose fragments that would otherwise shield residual lignin from chlorine dioxide. Subsequent D0–Eop–D1 bleaching uses ClO₂ charge adjusted to the 12–14 kappa number; peroxide in the extraction stage is held at 2.0–3.0% and NaOH at 1.0–1.5%. Final brightness measured to ISO 2470-1 reaches 82–84%, and viscosity measured to ISO 5351 remains above 600 mL/g. Residual ash measured to ISO 1762 is held below 0.5% w/w for fine printing grades because silica above this threshold creates blade scratches and dusting in sheeting. Permanent paper may meet ISO 9706 requirements if the alkaline reserve exceeds 20 g/kg calcium carbonate. If the enzyme stage is omitted, the same brightness target requires 0.5–1.0 percentage point additional peroxide and still produces lower opacity and higher brightness reversion under accelerated ageing.
Napier grass and related high-pectin species respond to endo-polygalacturonase addition only after pectin methyl groups are saponified by alkaline pre-treatment. In molded fiber lines, the alkaline soak at pH 9–10 and 70–80 °C is maintained for 40–60 min with enzyme dosed at 0.08–0.25% w/w OD grass. The pectinase fraction reduces pectic gel viscosity, while endoxylanase opens fiber cell wall pores. Target freeness is 500–600 mL CSF by ISO 5267-1, because lower freeness increases forming time and section thickness variation. Vacuum forming pressure differentials of 0.60–0.85 bar across the screened mold produce uniform mat density, and hot pressing at 180–200 °C for 15–30 s at 0.5–1.0 MPa plasticizes residual lignin and closes surface pores. Terminal articles include clamshell containers, plates, and cup carriers for dry or aqueous food contact. Food-contact grades are tested for aqueous and fatty simulant migration under FDA 21 CFR 176.170 and for overall migration under EU 1935/2004 plus BfR XXXVI/2. Production lots from grass furnish with pectin content above 6% w/w show improved thickness uniformity and fewer pinholes, but overdosing above 0.30% w/w OD increases wet fines and reduces wet strength retention through the transfer mold, requiring higher cationic retention polymer addition. Production-scale observation indicates that switching from hammer-milled whole stalk to shredder-chipped material with enzyme treatment reduces press cycle time by 8–12% and cuts trim waste from edge cracking.
Downstream, spinneret pack life in viscose extrusion responds to non-cellulosic impurities that pass the cold caustic extraction step. Grass dissolving pulp produced from Arundo donax or switchgrass requires alpha-cellulose above 92% w/w by TAPPI T 203, ash below 0.10% w/w by ISO 1762, and silicon below 0.05% w/w. Prehydrolysis at 165–175 °C dissolves hemicellulose, but the remaining short-chain xylan must be cleaved by purified endoxylanase before alkaline extraction. Enzyme is dosed at 0.05–0.10% w/w OD pulp, pH 7.0–8.0, 55 °C for 60 min, followed by cold caustic extraction with 8–12% NaOH at 30–40 °C. The extraction removes hemicellulose and reduces ash, while viscosity measured by ISO 5351 is retained above 450 mL/g to avoid brittle viscose dope. Bench-scale data for grass dissolving pulp are summarized in the comparative table below; published mill-scale data for this specific configuration is limited because most dissolving pulp lines remain softwood-based.
| Parameter | Control | Xylanase 0.05% | Xylanase 0.10% | Method |
|---|---|---|---|---|
| Alpha-cellulose, % w/w | 90.2 | 92.1 | 93.0 | TAPPI T 203 |
| Viscosity, mL/g | 635 | 610 | 575 | ISO 5351 |
| Ash, % w/w | 0.18 | 0.12 | 0.09 | ISO 1762 |
| Brightness, % | 87.0 | 87.5 | 88.0 | ISO 2470-1 |
Caustic extraction without enzymatic pre-treatment leaves residual xylan that raises dope filtration plugging value and increases spinneret cleaning frequency.
On tissue machines running high-dryness creping, the tensile-to-bulk trade-off shifts after mild endoglucanase exposure. Grass furnish beaten to 30 °SR without enzyme treatment develops a high fines fraction that lowers bulk and increases dusting in converting. Dosing a low-background exo-acting cellulase at 0.02–0.05% w/w OD pulp, pH 6.5–7.5, 50 °C for 30–60 min before the disc refiner reduces specific refining energy by 15–25% and preserves length-weighted fiber length. Bulk measured by ISO 534 increases by 5–8%, while dry tensile index measured by ISO 1924-2 remains within 8.5–10.5 N·m/g. Creping at 4.5–6.0% moisture on a Yankee cylinder is more stable because enzymatic pre-refining narrows the fines distribution. Direct food-contact tissue grades comply with FDA 21 CFR 176.170 for aqueous and dry food categories. Overdosing above 0.08% w/w OD reduces tensile index below 7 N·m/g, causing web breaks in the reel and converting lines.
Because mechanical fibrillation of dried grass pulp consumes specific energy in the upper range of published softwood data, endoglucanase pre-treatment is applied to reduce the number of passes through high-pressure homogenization. Bleached grass pulp at 2.0% w/w consistency is treated with endoglucanase at 0.03–0.08% w/w OD, pH 5.5–6.5, 50–60 °C for 45–60 min. The treated pulp is then passed through a microfluidizer at 1200–1500 bar with 400 µm interaction chambers. Laboratory-scale results indicate that pass count to reach 90% transmittance at 600 nm in a 0.1% dispersion drops from 8–10 passes to 5–6 passes; final gel viscosity at 1% solids is retained above 30 Pa·s at 10 s⁻¹. The microfibrillated cellulose is applied as a barrier layer additive in paperboard and as a strength agent in lightweight grass papers. Published data for grass-derived MFC are limited, and results differ sharply between species because cuticle wax and residual silica affect homogenizer chamber wear and dispersion stability.
Adding a pectinase–xylanase blend to a two-stage chemi-mechanical grass line reduces peroxide demand by limiting alkali-darkening precursors. Grass chips are steamed at 80–90 °C, impregnated with enzyme at 0.10–0.20% w/w OD, pH 7.0–8.0, and held 30 min before refining. After primary refining and screening, alkaline peroxide stabilised with silicate and DTPA is applied at 1.5–2.0% H₂O₂ instead of 2.5–3.0%. Brightness measured to ISO 2470-1 reaches 56–60%, acceptable for newsprint and directory grades. Process control targets 120–150 mL CSF after secondary refining and rejects below 0.05% on the 0.15 mm slotted screen. This grade is generally not suitable for direct food contact without a barrier layer.
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Grass Raw Material Pulping Enzymes are supplied as a multi-enzyme preparation for selective hydrolysis of non-cellulosic structural polysaccharides in non-wood pulping feedstocks. The liquid product is designated GRPE-450; the spray-dried powder is designated GRPE-450C. The formulation contains endo-1,4-β-xylanase (EC 3.2.1.8), endo-1,4-β-glucanase (EC 3.2.1.4), cellobiohydrolase (EC 3.2.1.91), β-glucosidase (EC 3.2.1.21), pectin lyase (EC 4.2.2.10), and feruloyl esterase (EC 3.1.1.73). Application targets are wheat straw, rice straw, switchgrass, and miscanthus prior to mechanical refining or low-alkali soda pulping. The formulation is not a replacement for alkaline delignification; it is a pretreatment that modifies the grass cell-wall matrix to reduce downstream mechanical and chemical energy input. The distinguishing compositional feature is feruloyl esterase activity, which cleaves the hydroxycinnamate–arabinoxylan ester linkages that are abundant in grass fiber but largely absent in softwood and most hardwood cell walls.
Enzyme activity is quantified by substrate-specific reducing-sugar release. Xylanase is determined with birchwood xylan at pH 5.5 and 50°C; cellulase is determined by the IUPAC filter paper method at pH 4.8 and 50°C; pectinase is determined with polygalacturonic acid at pH 4.5 and 45°C; feruloyl esterase is determined with methyl ferulate at pH 6.0 and 37°C. These assay conditions define the activity units in the specification matrix and should not be interpreted as full process optima. The product also contains low-temperature stabilizers in the liquid form and maltodextrin carrier in the powder form, which influence reconstitution and viscosity behaviour but do not contribute hydrolytic activity.
Grass stems and leaves present a diffusion barrier not encountered in wood chips. The outer epidermis of rice straw and wheat straw contains a dense cuticle and silica cell layer; rice straw ash content is commonly 10–20 wt% dry matter, while wheat straw falls between 4–9 wt%. The silica bodies are not hydrolyzed by any component of the preparation, and they restrict uniform penetration of the high-molecular-mass xylanase and pectin lyase fractions. Mechanical size reduction below 30 mm and pressed extraction of soluble salts are therefore mandatory before enzyme addition. In the internode parenchyma, ferulic acid esterified to arabinoxylan participates in oxidative cross-linking with lignin through 4-O-β-D-xylopyranoside bridges and 5,5′-diferulate dimers. These ester bonds are alkali-labile but require enzymatic cleavage at the accessible surface if subsequent refining is to achieve fiber separation without excessive cutting. Published data for this specific enzyme configuration in high-silica grass is limited; the biochemical accessibility constraints are documented in non-wood biomass structural studies using acetylated xylan and lignin model compounds.
High ash also introduces pH buffering and soluble silicate. Residual sodium carbonate from upstream washing raises the enzyme-impregnation pH above 6.5, where feruloyl esterase loses more than 50% of its pH 6.0 activity within 30 min. Process water with total alkalinity above 200 mg/L as CaCO₃ should be pH-adjusted before enzyme dilution. A buffer strength of 10–20 mM sodium acetate or ammonium sulfate improves enzyme binding by reducing electrostatic repulsion between carboxylated uronic acids in the cell wall and the protein surface. Hard water containing calcium above 150 mg/L can also intensify pectin gelation; in such water the enzyme solution should be prepared with a chelator suitable for the mill’s wastewater discharge permit.
The release specification envelope is listed in the table below. The values are representative manufacturing targets for commercial batches, not guaranteed process-efficacy limits for a particular furnish.
| Parameter | GRPE-450 liquid | GRPE-450C powder | Test method |
|---|---|---|---|
| Appearance | Amber to brown liquid | Off-white to tan powder | Visual inspection at 25°C |
| Density / bulk density | 1.05–1.15 g/cm³ | 0.45–0.60 g/cm³ | ASTM D4052; ISO 60 |
| pH | 4.5–5.5 | 6.0–7.0 in 1% solution | ISO 787-9 |
| Endo-1,4-β-xylanase | ≥5,000 XU/mL | ≥20,000 XU/g | DNS reducing sugar, birchwood xylan, pH 5.5, 50°C |
| Filter paper cellulase | ≥500 FPU/mL | ≥2,000 FPU/g | IUPAC Ghose, pH 4.8, 50°C |
| Pectinase | ≥1,000 PGU/mL | ≥5,000 PGU/g | DNS reducing sugar, polygalacturonic acid, pH 4.5, 45°C |
| Feruloyl esterase | ≥200 FEU/mL | ≥800 FEU/g | HPLC, methyl ferulate, pH 6.0, 37°C |
| Total heavy metals | ≤20 mg/kg | ≤20 mg/kg | ISO 17294-2 |
| Total viable count | ≤10,000 CFU/mL | ≤10,000 CFU/g | ISO 4833-1 |
Storage stability for GRPE-450 liquid at 25°C shows less than 10% loss of xylanase activity after 12 months; freeze–thaw cycles beyond 3 cause irreversible precipitation of the pectin lyase fraction. GRPE-450C retains ≥90% filter paper cellulase activity after 12 months at 30°C when sealed against humidity. Both products should be stored away from strong oxidizers, cationic surfactants, and free chlorine sources.
The intended process insertion is after feedstock screening and screw pressing, before a high-consistency twin-screw impregnator. Chopped material is adjusted to 25–35% consistency and loaded into a twin-screw unit with an L/D ratio of 40:1. The enzyme solution is prepared by diluting GRPE-450 1:5 to 1:10 in tempered water at 35–45°C. Liquid dose is 0.05–0.20 wt% of dry fiber; GRPE-450C is reconstituted at 1:4 and applied at 0.01–0.04 wt%. The configured pH at injection should be 5.0–5.5. Barrel temperature setpoints are 45°C in the feed zone and 55°C in the discharge zone; residence time is 90–180 s. After extruder discharge, the treated material is held for 60–120 min at 50°C in a plug-flow reactor or unjacketed chest before entering disc refining or soda cooking.
In refining applications, enzyme treatment reduces specific energy consumption at constant Canadian Standard Freeness measured by ISO 5267-2. Published enzyme-assisted refining studies on wood indicate specific energy reductions of 10–25%; for grass raw materials, mill data are limited, and a baseline trial should compare the same refiner fillings and feed consistency before adjusting dose. The action of feruloyl esterase loosens the fibril network, shifting the fiber length distribution toward lower fines generation as measured by automated optical fiber analysis conforming to ISO 16065-2. When the same stock is characterized by Schopper-Riegler drainage under ISO 5267-1, the response is nonlinear: underdosing below 0.05 wt% can increase fines by creating partially hydrolyzed polysaccharide fragments without sufficient ester cleavage to release fiber bundles.
Specific energy consumption at constant Canadian Standard Freeness is the primary control parameter. In disc refining, the refiner gap should not be adjusted simultaneously with enzyme dose; the no-load energy and fiber residence time interact with enzyme-softened fiber and can produce a false apparent energy reduction. A startup sequence should hold refiner load constant for 30 min after enzyme addition before changing dilution water.
In soda cooking, the enzyme stage is not a replacement for sodium hydroxide. Typical soda cooks for wheat straw use 12–18 wt% NaOH on dry fiber at 160–170°C to achieve kappa number below 20 under ISO 302. Enzyme preimpregnation can lower the alkali charge by 5–15% or reduce total cooking time at the same alkali charge, but this response depends on feedstock ash, harvest maturity, and storage-induced fermentation. Feruloyl esterase activity decreases as ensiled grass ages; bacterial fermentation during storage converts free ferulic acid and reduces the accessible ester substrate. Freshly processed or dried grass therefore demonstrates a more consistent enzyme response than long-stored wet bales.
In soda mills that recycle weak black liquor for pre-wetting, enzyme addition directly into black liquor is incompatible: the pH is typically above 12, and dissolved lignin and silicate bind to the enzyme protein. The recommended sequence is fresh-water screw pressing to displace black liquor before enzyme addition. If weak black liquor is used to reach impregnation consistency, pH adjustment to 5.5 may require acid volumes that introduce sodium acetate or citrate buffers and increase sodium load in the recovery cycle. The preferred strategy is a separate enzyme stage after washing and before chemical cooking.
Temperature and pH windows are not symmetrical. Below 40°C, pectin lyase action slows substantially; above 60°C, the filter paper cellulase component denatures with a measured half-life of approximately 18 min at 65°C in buffer. Residual chlorine in process water above 0.5 mg/L inactivates xylanase through methionine oxidation; the use of chlorine dioxide or chlorination upstream requires dechlorination or holding until free chlorine is undetectable. Copper and iron ions above 10 mg/L suppress pectin lyase by binding to the active-site polysaccharide recognition groove. Do not combine with amine-based wet-strength additives or strongly cationic retention aids at the same addition point because polyelectrolyte complexes precipitate the enzyme protein and reduce accessible active sites. If the liquid product has been frozen, thaw at 10–15°C and mix with low-shear agitation; high-shear dispersers above 1,000 rpm can denature the cellulase complex by interfacial shear at air–liquid boundaries.
GRPE-450 liquid is shipped ready to dilute; GRPE-450C is preferred where freight weight and liquid handling are constrained. The powder form contains maltodextrin carrier and requires reconstitution under gentle agitation. The two forms are equivalent in enzyme activity ratio but differ in bulk density and storage footprint. The powder form should be added to water, not water to powder, to avoid lumping and localized heat generation during rehydration.
Compared with xylanase-only pulping additives, the inclusion of feruloyl esterase and pectin lyase changes the substrate profile. Xylanase-only products cleave internal β-1,4-xylosidic linkages but leave feruloyl ester bridges intact; the resulting arabinoxylan fragments remain esterified and can maintain cross-links to lignin. In grass feedstocks, ferulate content ranges from 0.2–1.0 g/kg dry matter in wheat straw to 1.0–3.0 g/kg in maize stover, according to published compositional surveys. By cleaving the ferulate ester, GRPE-450 reduces crosslink density without requiring alkaline saponification; the same ester cleavage occurs in soda cooking only at high pH and temperature. Compared with cellulase-only additives, GRPE-450 maintains a filter paper cellulase to xylanase activity ratio near 1:10, which is intended to preserve cellulose degree of polymerization. Cellulase-only products applied at high dose reduce pulp viscosity measured by ISO 5351 and can weaken tensile strength measured by ISO 1924-2 if treatment time exceeds 120 min.
Against a conventional alkaline soda process without enzymes, the enzyme preparation operates in a lower thermal range and has no capacity to remove esterified or etherified lignin fragments by solvation. The alkali reduction effect is therefore a consequence of improved liquor penetration through the enzyme-loosened pectin–ferulate matrix, not a direct delignification effect. Enzyme treatment does not reduce the silica content of grass pulp; silica removal remains dependent on alkaline extraction and alkali recovery limitations. In high-silica operations, the enzyme-treated pulp still requires washing with dilute sodium hydroxide or sodium carbonate to remove silicate deposits in evaporators. Published data for this specific enzyme configuration in full-scale high-silica grass pulping is limited; pilot trials with the target feedstock and process water are required to establish dose-response curves and alkali savings.
