Pulpzyme HC Research Articles

Response surface methodology optimization study on corncob pretreatment: reduction of sodium hydroxide usage and enhancement in pulpzyme HC biobleaching efficiency

Lignocellulosic rich corncob biomass possesses less complex structure, lignin and pigment content. As compared to wood pulp, it is considered to be a better alternative for the production of cellulose fibre. The present study was conducted to optimize both the alkaline (using sodium hydroxide) and biobleaching (using Pulpzyme HC) pretreatment process of corncob to promote lignin removal and cellulose swelling. It was the aim of this work to achieve mild processing conditions for corncob pretreatment in order to minimize the chemical usage. Results demonstrated that the mild pretreatment approach employed was found to successfully increase cellulose swelling and lignin removal from the corncob biomass. In alkaline pretreatment process, reaction temperature showed to be the most prominent effect in enhancing lignin removal and cellulose swelling as compared to sodium hydroxide concentration and reaction time. RSM optimized conditions for alkaline pretreatment process: 0.5 M NaOH, reaction temperature of 80°C and reaction time of 30 mins manage to increase the sedimentation index (indicate swelling of cellulose) from 0 to 30 and reduce the kappa number (represent lignin removal) from 82 to 32, respectively. Meanwhile, for biobleaching pretreatment using Pulpzyme HC, reaction time play a more significant role than the Pulpzyme HC concentration in promoting lignin removal and increasing cellulose swelling. RSM optimized conditions showed that the kappa number was reduced from 32 to 18 whereas the sedimentation index increased from 30 to 60 when the alkaline pretreated corncob was biobleached with Pulpzyme HC.

PREPARATION OF DYED AZOLIGNINS ON LINEN COTTONIN MODIFIED BY ENZYMES

The possibility of using azoreaction for obtaining colored like-cotton flax (cottonin) are evaluated in this article. For the process of disfiling (disfibering, disenchantment) enzymes Pulpzyme HC and Scourzyme L ("Novozymes A/S" (Denmark)) were applied. Diazol scarlet K was used as a diazo component. It is established that the enzymatic modification of ligno-carbohydrate complex promotes opening phenolic hydroxyls. As a result, the reactivity of flax fiber with respect to diazol alum K increases. The spectra of dyed extracted polyphenols of flax were obtained and interpreted for region of 400-700 nm. It was shown that in the spectra of extractive aromatic substances of phenolic nature for the native fiber two maxima at 420-440 nm and 500-520 were appeared nm during the azo coupling reaction. The first maximum corresponds to the compounds formed as a result of the reaction of azo combination with aromatic substances having unexpressed color (chromophore). The long-wave maximum is associated with azo lignins, where the associated and non-associated complexes of aromatic polyphenols of lignin act as the diazocomponent. It is assumed that enzymatic hydrolysis of non-cellulose polysaccharides creates stereo accessibility to the reaction groups of lignin, which is part of the structure of the ligno-carbohydrate complex of flax fiber. The dependence of the function K/S – (K/S)0 for colored flax fibers at different modification methods were obtained and interpreted. The effect of lignin unblocking in after enzymatic cottonization is confirmed. There is a significant increase in the K/S function of colored cottonin in comparison with the results for native short flax fiber. The method of spectrophotometry proved that the maximum effect of color dyeing is provided in the case of the enzymatic modification of Pulpzyme NS if excluded of the washing stage.

Mesophilic anaerobic co-digestion of cow manure with three-phase olive mill solid waste

ABSTRACTThe biogas production potential of different mixtures of cow manure (CM) and three-phase olive mill solid waste (3POMSW) at 37°C was evaluated. Results showed that 3POMSW produced more methane yield than CM. In the anaerobic co-digestion (AcoD) methane yield increased with increasing of 3POMSW content, the maximum methane yield was observed at 3POMSW:CM ratio of 3:1. Addition of an enzyme mixture (Celluclast, Pulpzyme HC, Sherazyme, Novozym 342, and Resinase A 2X) to the 1:1 mixture increased the quantity and quality of biogas production and reduced the retention time required to achieve a high rate of biodegradation. Therefore, AcoD with enzymes was an effective way to improve the methane yield of 3POMSW and CM.

Enzyme treated CNF biofilms: Characterization

The objective of this study was to characterize on the chemical, mechanical, electrical and thermal properties of nanofibrillated cellulose based polyvinyl alcohol (PCNF) and silica (SiCNF) films obtained from Pulpzyme HC 2500 and Celluclast 1.5 L enzyme treated kraft-NaBH4 pulps. Morphological alterations were monitored with SEM. Thermal stability, chemical characterization and crystallization were determined using TGA and FT-IR. Young's and storage moduli of the films were determined via a universal testing machine and DTMA. Dielectric properties were evaluated using an impedance analyzer. In the PCNF films, new vibrations and chemical shifts were observed. The crystallinity values of the SiCNF films calculated from the FT-IR were in agreement with the TGA results, revealing that the lowest crystallinity value was in the SiCNF. The higher Young modulus and elongation at break value were obtained in the neat the CNF films while the lowest values were observed in the neat SiCNF films. However, the SiCNF films revealed higher thermo-mechanical property. The PCNF and SiCNF films exhibit more visible dielectric behavior than that of the neat CNF films. Higher thermal stability, thermo-mechanical and mechanical properties were determined in the Pulpzyme HC 2500 enzyme treated films. Hence, this study evidenced that the properties of CNF films having different matrix are influenced by both the enzymes employed.

Matrix impact on the mechanical, thermal and electrical properties of microfluidized nanofibrillated cellulose composites

Abstract This study reports on the effect of organic polyvinyl alcohol (PVA) and silica matrix on the properties of cellulose-based nanocomposites. Nanofibrillated cellulose was isolated from kraft pulp and treated with Pulpzyme HC 2500 enzyme prior to high-pressure homogenization in order to lower energy consumption. Three nanocomposite films were fabricated via the casting process: nanofibrillated cellulose, nanocellulose-PVA (NC-PVA) and nanocellulose-silica (NC-Si). Chemical characterization and crystallization were determined with FTIR. Thermal stability was investigated with thermogravimetric analysis. Morphological alterations were monitored with scanning electron microscopy. A universal testing machine and dynamic mechanical thermal analysis were used for determination of Young’s and storage moduli. The real and imaginary parts of permittivity and electric modulus were evaluated using an impedance analyzer. Considerable alterations were seen under FTIR. Thermal stability was lower in NC-Si than in NC-PVA due to lower crystallinity. Higher Young’s modulus and storage moduli were observed in NC-PVA than in NC-Si. NC-PVA exhibited a singular relaxation process, while a double relaxation process was seen in NC-Si. Consequently, the nanocomposite film prepared from the organic matrix (NC-PVA) had a mechanical advantage for industrial applications. However, neat NC composite revealed the highest storage modulus and thermal stability.

Enzymatic treatment applied as a final stage in E. globulus kraft pulp bleaching

AbstractBACKGROUNDBrightness stability of bleached chemical pulps is often associated with the final bleaching stages that should provide the removal of chromogenic species responsible for brightness reversion without compromising the papermaking potential. Aiming at promoting higher brightness stability, a partially bleached Eucalyptus globulus pulp (DED) of c. 88% ISO brightness was involved in a study of a final enzymatic stage (X) alternative to conventional chlorine dioxide (D) and hydrogen peroxide (P) bleaching stages (DEDX vs. DEDD and DEDX vs. DEDP). X stage was also applied before and after the final P or D stages (DEDDX/DEDXD and DEDPX/DEDXP) to produce high brightness pulps (c. 91%).RESULTSX stage with xylanase Pulpzyme HC allowed an increase of c. 1.5% in pulp brightness while decreasing the brightness reversion and a concomitant pulp yield loss of only 0.5%. Significant chemical savings were obtained in the final D (70%) or P (45%) stages to achieve targeted final brightness of c. 91%. DEDXD or DEDXP sequences had advantage over DEDDX and DEDPX, respectively, in terms of brightness stability of fully bleached pulps.CONCLUSIONSXylanase interferes with structures responsible for the brightness reversion. X stage allows production of pulp with extra brightness in sequences with a final P stage. © 2014 Society of Chemical Industry

Contribution of xylan to the brightness development and stability in the final ECF bleaching of eucalypt (Eucalyptus globulus Labill.) kraft pulp

Abstract Xylans isolated from eucalypt kraft pulps have been characterized by modern analytical methods. The pulps were partially bleached (DEOPD) and fully bleached with either a final ClO2 (DEOPDD) or an alkaline H2O2 (DEOPDP) bleaching stage. Alternatively, xylan isolated from the DEOPD pulp was treated with ClO2 or with H2O2 under the same conditions as pulps in a final bleaching stage and were further characterized. 1H nuclear magnetic resonance, size exclusion chromatography, UV-vis spectroscopy in cadoxen solution, and UV-resonance Raman spectroscopy were applied as analytical methods. The final ClO2 stage generated new unsaturated moieties in xylan, whereas H2O2 was very effective in the removal of xylan-related chromophores. The role of xylan to the delay of brightness development in the final ClO2 stage was highlighted by means of a pretreatment with xylanase Pulpzyme HC before the final bleaching stage. By this approach, the final bleachability of the pulp was boosted and the brightness stability of the fully bleached pulp was improved.

Wetstorage of Bagasse with Hemicellulase

In this paper, the effect of hemicellulase treatment on the properties of bagasse and treatment liquor was investigated, and the chemical components of bagasse after optimized hemicellulase treatment were compared with those of wet-stored bagasse. The research results showed that small molecular sugar and lignin in bagasse were dissolved in hemicellulase treatment process, and most of the sugar was non reducing sugar. The lignin dissolution rate of hemicellulase treatment was twice as much as that of wet storage, and hemicellulase treatment had relatively smaller effect on carbohydrate, especially to cellulose. In addition, the improving effect of bagasse properties with pulpzyme HC treatment was better than that of Nz51024 treatment.

Bleach boosting effect of xylanase A from Bacillus halodurans C-125 in ECF bleaching of wheat straw pulp

Past studies have revealed major difficulties in applications of xylanase in the pulp and paper industry as enzymes isolated from many different species could not tolerate high temperatures or highly alkaline conditions. The thermostable xylanase A from Bacillus halodurans C-125 (C-125 xylanase A) was successfully cloned and expressed in Pichia pastoris with a yield as high as 3361U/mL in a 2L reactor. Its thermophilic and basophilic properties (optimal activity at 70°C and pH 9.0), together with the fact it is cellulase-free, render this enzyme attractive for compatible applications in the pulp and paper industry. The pretreatment of wheat straw pulp with C-125 xylanase A at pH 9.0 and 70°C for 90min induced the release of both chromophores (Ab237, Ab254, Ab280) and hydrophobic compounds (Ab465) into the filtrate as well as sugar degradation. Moreover, the addition of 10U xylanase to 1g wheat straw pulp (dry weight) as pretreatment improved brightness by 5.2% ISO and decreased the kappa number by 5.0% when followed by hydrogen peroxide bleaching. In addition, compared with two commercial enzymes, Pulpzyme HC and AU-PE89, which are normally incorporated in ECF bleaching of wheat straw pulp, C-125 xylanase A proved to be more effective in enhancing brightness as well as preserving paper strength properties. When evaluating the physical properties of pulp samples, such as tensile index, tearing index, bursting index, and post-color (PC) number, the enzymes involved in pretreating pulps exhibited better or the same performances as chemical treatment. Compared with chemical bleaching, chlorine consumption can be significantly reduced by 10% for xylanase-pretreated wheat straw pulp while maintaining the brightness together with the kappa number at the same level. Scanning electron microscopy revealed significant surface modification of enzyme-pretreated pulp fibers with no marked fiber disruptions.

Modification of Bleached Softwood Pulp with Xylanase

Xylanse named as Pulpzyme HC was used to modify bleached softwood pulp before refining. The efficiency of modification by different enzyme dosage was invested in this paper. The result showed that enzymatic treatment decreased the dissolved charge and absolute Zeta potential of the slurry and increased the fiber surface wettability. Appropriate Pulpzyme HC (0.4u/g) could improve the refining efficiency by 9.5°SR. The brightness and bulk of hand sheets increased with the increasing of the enzyme. Tensile index and tear index of hand sheets reached the maximum at the enzyme dosage of 0.2u/g. In this dosage, fiber length, knot index and curl index of fiber increased. But excessive enzyme decreased the tear index and had no effect on the tensile index.

Enzymatic Processing of Rice Husk Autohydrolysis Products for Obtaining Low Molecular Weight Oligosaccharides

Rice husks were enzymatically treated in aqueous media to cause the hydrolytic degradation of xylan. The reaction liquors (raw or refined by nanofiltration and ion exchange) were treated with endoxylanases to reduce the degree of polymerisation (DP) of the reaction products. Operating at the optimal temperature and pH of each enzyme, the effects of enzyme loading and reaction time were assessed. The enzyme Shearzyme 2x led to the highest proportion of oligomers with DP in the range 2–3, whereas the other endoxylanases (Pentopan Mono BG and Pulpzyme HC) gave mainly oligomers with DP in the range 4–5 or 6–7.

Xylanase recycling for the economical biobleaching of sugarcane bagasse and straw pulps

In this work, the applicability of xylanases in sugarcane straw pulps and the possibility of recovering this enzyme were evaluated. A commercial xylanase (Pulpzyme HC) was used for pulp treatment and this enzyme was recovered and reused several times in the new pulp enzymatic treatment without addition of new enzyme load. In addition, a combined process of pulping was also evaluated, such as the fungal pretreatment of straw (biopulping) and the acetosolv pulping. Quantity of recovered enzyme in the first treatment was approximately 7% of initial enzyme load. After the second treatment no enzyme recovery was possible. Several factors interfered on xylanase recovery, such as pulp type, treatment medium (buffered or aqueous) and the methodology employed in the enzyme recovery. An alkaline extraction stage was carried out to verify the action of Pulpzyme on enzymatic treated pulps, but due to concentration of NaOH used in the stage differences were not observed in the kappa numbers and viscosity of the pulps. The Fourier transform infrared and principal component analyses (FTIR–PCA) were used to analyze sugarcane bagasse pulps of a previous work and FTIR–PCA showed differences among untreated, xylanase-treated and alkaline-extracted pulps of sugarcane bagasse.

Degradation of Lignin-Containing Materials by Xylanase in Biopreparation of Cotton

Solubilization of lignin and carbohydrates from the lignin-holocellulose structure of cotton seed-coat fragments was investigated by UV/VIS spectrometry. Xylanase (Pulpzyme HC) pre-treatment partially destroyed the lignocellulosic structure of the seed-coat fragments, producing reducing sugars and soluble lignin in the supernatant. Furthermore, the pre-treatment by enzyme enhanced the delignification in the subsequent alkaline scouring process and increased the lightness of the substrate.

Role of the EDTA Chelating Agent in Bioscouring of Cotton

Our previous work demonstrated that ethylenediamine-tetra-acetic acid (EDTA) markedly enhances the apparent activity of commercial xylanase and pectinase enzymes in cotton bioscouring, accelerating degradation and removal of impurities. In this study, we explore how EDTA can improve the efficiency of the enzyme process in cotton bioscouring. The effects of EDTA on the enzyme action and degradation of seed-coat fragments—the most resistant natural impurities of cotton to be degraded in bioscouring—are investigated. Results show that application of EDTA in different concentrations does not inhibit the main activities of the enzymes investigated. Thus, the pectinase activity of Viscozyme 120L and the xylanase activity of Pulpzyme HC remain almost unchanged. On the other hand, EDTA modifies the substrate structure by removing the calcium ions from the cross bridges that link the macromolecules in pectin to one another or pectin to other polysaccharides. While EDTA pretreatment significantly decreases the efficiency of enzymatic hydrolysis monitored by reducing sugar liberation, simultaneous application of EDTA and enzyme in one treatment bath largely accelerates the degree of hydrolysis, indicating a synergistic effect of enzyme and EDTA.

Compatibility of alkaline xylanases from an alkaliphilic Bacillus NCL (87-6-10) with commercial detergents and proteases.

Alkaline xylanases from alkaliphilic Bacillus strains NCL (87-6-10) and Sam III were compared with the commercial xylanases Pulpzyme HC and Biopulp for their compatibility with detergents and proteases for laundry applications. Among the four xylanases evaluated, the enzyme from the alkaliphilic Bacillus strain NCL (87-6-10) was the most compatible. The enzyme retained its full activity (40 degrees C for 1 h) in the presence of detergents, whereas Pulpzyme HC and Sam III showed only 30% and 50% of their initial activity, respectively. Biopulp, though stable to detergents, had only marginal activity (5%)at pH 10. However, all four enzymes retained significant activity (80%) for 60 min in the presence of the proteases Alcalase and Conidiobolus protease. Supplementation of the enzyme enhanced the cleaning ability of the detergents.

Enzymes and chelating agent in cotton pretreatment

Desized cotton fabric and cotton seed-coat fragments (impurities) have been treated with commercial cellulase (Celluclast 1.5 L), hemicellulase–pectinase (Viscozyme 120 L) and xylanase (Pulpzyme HC) enzymes. Seed-coat fragments hydrolyzed much faster than the cotton fabric itself. This relative difference in hydrolysis rates makes possible a direct enzymatic removal of seed-coat fragments from desized cotton fabric. Addition of chelating agents such as ethylenediamine-tetra-acetic acid (EDTA) markedly enhanced the directed enzyme action. Pretreatments carried out in acidic solution at pH 5 increased the lightness of seed-coat fragments, contrary to the samples treated in neutral medium at pH 7. Alkaline scouring resulted in darker seed-coat fragments except for the samples pretreated with Pulpzyme HC plus EDTA. This effect is similar to that observed in the biobleaching process in pulp and paper industry.

Bleaching of Kraft Pulp with Commercial Xylanases

The performance of commercial xylanases in totally chlorine-free bleaching of kraft pulp from conifer was tested with Pulpzyme HC (Novo Nordisk) and Cartazyme NS-10 (Sandoz/Clariant), at 500 U/kg of dry pulp, respectively. The treatment with Pulpzyme (XP) or Cartazyme (XC) has been combined with stages of bleaching using: oxygen (O), sulfuric acid (A), and extraction with hydrogen peroxide (EOP). The following sequences have been tested: OXpAEOP, OXcAEOP, XpOAEOP, XcOAEOP, and OAEOP. Kraft pulp bleached at the Klabin industrial plant using the sequence, CEH (chlorine, alkaline extraction, and hypochlorination) was used for comparison. The following average values were obtained: 1. Kappa number: OXPAEOP, 4.8; OXCAEOP, 4.9; XPOAEOP, 5.0; XCOAEOP, 4.9; OAEOP, 5.6, and CEH, 1.9; 2. Brightness (% ISO values): OXPAEOP, 68.4; OXCAEOP, 70.1; XPOAEOP, 67.9; XcOAEOP, 68.8; OAEOP, 63.8, and CEH, 63.6; and 3. Viscosity (cP): OXPAEOP, 27.6; OXCAEOP, 26.9; XPOAEOP, 23.4; XCOAEOP, 23.1; OAEOP, 25.4, and CEH, 25.2. Pulps that were treated with xylanases, before or after the delignification with oxygen, have shown reduced kappa number and higher brightness than the pulp OAEOP. Enzyme treatment before delignification with oxygen reduces pulp viscosity. Brightness obtained for pulp produced with bleaching sequences containing the enzymatic treatment, when compared with the control, CEH, shows that the xylanases enhance the action of the bleaching agents.

Adsorption of a xylanase purified from Pulpzyme HC onto alkali-lignin and crystalline cellulose

Adsorption of a xylanase purified from a commercial xylanase, Pulpzyme HC, onto two model components of kraft pulp, crystalline cellulose (Avicel) and alkali-lignin (Indulin AT), was studied at 40°C. A considerable amount of the purified xylanase was adsorbed onto alkali-lignin in alkaline solutions. The adsorption of the purified xylanase onto crystalline cellulose was not significant and could be described by the Langmuir-type adsorption isotherm. The adsorption of the purified xylanase onto alkali-lignin was assumed to be caused by physical or van der Waals interaction based on the result that NaCl did not change the adsorption isotherm. © Rapid Science Ltd. 1998

Effects of surfactants on the enzymatic bleaching of kraft pulp by xylanase

A xylanase was purified from a commercial crude xylanase, Pulpzyme HC, and used for the bleaching of kraft pulp in the absence or in the presence of nonionic surfactants, Tween 20, Tween 80, and Igepal C930. The purified xylanase has a molecular weight of 23,500 as determined by a reducing SDS-PAGE. Tween 20 was most effective to enhance the efficiency of the enzymatic bleaching of kraft pulp by xylanase.

Use of enzymes in modification of fibres for improved beatability

The effectiveness of several commercial enzymes has been evaluated for energy savings in beating and refining. A number of unbleached kraft pulps viz. softwood, bamboo and mixed pulp (60% waste corrugated kraft cuttings and 40% unbleached softwood pulp) were treated with the enzymes. With softwood pulp, the maximum reduction in beating time was found to be 25% in the case of hemicellulase ‘Amano’ 90 whereas in the case of Bleachzyme F, Irgazyme 40S, Pulpzyme HC and Cartazyme HS 10, the reduction in beating time was of the order of 17–22%. The enzyme-treated pulp retained the required strength properties except in the case of hemicellulase ‘Amano’ 90, where the strength properties of the pulp were slightly affected. With bamboo pulp and mixed pulp, treatment with Bleachzyme F and hemicellulase ‘Amano’ 90, reduced the beating time by about 18% and 15%, respectively. The strength properties of the pulp were not found to be affected.