Recombinant manganese peroxidase (rMnP) from Pichia pastoris. Part 2: Application in TCF and ECF bleaching

Holzforschung ◽  
2010 ◽  
Vol 64 (2) ◽  
Author(s):  
Haowen Xu ◽  
Gary M. Scott ◽  
Fei Jiang ◽  
Christine Kelly
Keyword(s):  
Pichia Pastoris ◽  
Manganese Peroxidase ◽  
Kraft Pulp ◽  
Energy Savings ◽  
Strength Properties ◽  
Enzymatic Treatment ◽  
Peroxide Bleaching ◽  
Alkaline Peroxide ◽  
Elemental Chlorine ◽  
Ecf Bleaching

AbstractThe recombinant manganese peroxidase (rMnP) produced from the yeastPichia pastorishas been investigated in totally chlorine free (TCF) and elemental chlorine free (ECF) bleaching sequences for improving the bleachability of kraft pulps. In TCF bleaching, oxygen delignified hardwood kraft pulp was treated with rMnP, followed by a sequence combining a chelating and alkaline peroxide bleaching stage. The inclusion of the enzymatic treatment significantly improved the pulp brightness to a level that is difficult to obtain by chemical bleaching alone. Furthermore, the treatment with rMnP resulted in energy savings during pulp refining with PFI mill with a slight improvement in pulp strength properties such as tensile index and burst index. In ECF bleaching, a significant reduction in chlorine dioxide consumption was obtained. A three-stage rMnP treatment combined with alkaline extraction, followed by DED bleaching sequence for hardwood kraft pulp (HWKP) or DEDED bleaching sequence for softwood kraft pulp (SWKP), reduced the total effective chlorine by 41% and 32% for HWKP and SWKP, respectively, compared with the conventional bleaching sequences without enzymatic treatment. The strength properties of the enzyme-treated pulp were also slightly better than that of the control pulp. Further reductions in the consumption of total effective chlorine were obtained when a xylanase pretreatment was incorporated into the bleaching sequence before the repeated rMnP treatment.

Application of pure, thermostable, alkali-tolerant xylanase in bleaching of oxygen-delignified pine kraft pulp

TAPPI Journal ◽  
2015 ◽  
Vol 14 (11) ◽  
pp. 689-694
Author(s):  
QINGZHI MA ◽  
QI WANG ◽  
CHU WANG ◽  
NIANJIE FENG ◽  
HUAMIN ZHAI
Keyword(s):  
Intrinsic Viscosity ◽  
Chlorine Dioxide ◽  
High Purity ◽  
Kraft Pulp ◽  
Alkaline Media ◽  
Industrial Scale ◽  
Elemental Chlorine ◽  
Effect Of Oxygen ◽  
Alkaline Tolerant ◽  
Ecf Bleaching

The effect of oxygen (O2)-delignified pine kraft pulp pretreatment by high-purity, thermostable, and alkaline-tolerant xylanases on elemental chlorine free (ECF) bleaching of O2-delignification kraft pulp was studied. The study found that xylanase pretreatment preserved the intrinsic viscosity and yield of O2-delignified pulp while causing about 7% of delignification with high delignification selectivity. The xylanases with high purity, higher thermostability (75°C~80°C) in highly alkaline media (pH 8.0~9.5) could be applied on an industrial scale. Pulp pretreatment by the high-purity, thermostable, and alkaline tolerant xylanases could improve pulp brightness or reduce the chlorine dioxide (ClO2) consumption. In a D0ED1D2 bleaching sequence using the same amount of ClO2, the xylanase-pretreated pulp obtained a higher brightness (88.2% vs. 89.7% ISO) at the enzyme dose of 2 U/g pulp; or for the same brightness as control (88.2% ISO), the ClO2 dosage in the D0 stage was reduced by 27%, which represents a 16% savings in total ClO2 used for bleaching.

Relationship between dissolution of fiber materials and development of pulp strength in alkaline peroxide bleaching of mechanical pulp

Holzforschung ◽  
2004 ◽  
Vol 58 (4) ◽  
pp. 369-375 ◽  
Author(s):  
G.X. Pan
Keyword(s):  
Carboxylic Acid ◽  
Acid Group ◽  
Strength Properties ◽  
Strength Development ◽  
Mechanical Pulp ◽  
Peroxide Bleaching ◽  
Alkaline Peroxide ◽  
Bonding Properties ◽  
Pulp Strength ◽  
Fiber Materials

Abstract This study elucidates the relationship between the dissolution of pulp components and the development of fiber bonding properties in alkaline peroxide bleaching of aspen mechanical pulp. In general, bleaching reactions cause the removal of pulp substances from the fibers, which in turn improves pulp strength properties. Nonetheless, alkaline hydrolysis is particularly important to the development of strength because this reaction mechanism plays a key role in imparting additional carboxylic acid groups onto the fibers. The strong correlation between fiber carboxylic acid group concentration and the amount of anionic dissolved substances makes it possible for us to predict the strength properties of bleached pulps by estimating the anionicity of bleaching filtrates using analytical methods such as cationic demand. The paper also provides insights into the importance of the alkalinity in peroxide bleaching to the dissolution of pulp materials and the strength development.

ECF Bleaching of Pre-Hydrolyzed Larix Kraft Pulp for Production of Dissolving Pulp

2013 ◽  
Vol 634-638 ◽  
pp. 386-390
Author(s):  
Zhi Li ◽  
Jun Li ◽  
Jun Xu
Keyword(s):  
Hydrogen Peroxide ◽  
Chlorine Dioxide ◽  
Kraft Pulp ◽  
Kappa Number ◽  
Alkaline Extraction ◽  
Polymerization Degree ◽  
Oxygen Delignification ◽  
Elemental Chlorine ◽  
Pulp Properties ◽  
Ecf Bleaching

Elemental Chlorine Free (ECF) bleaching sequence of O1/O2D0EOPD1D2 was adopted to bleach the pro-hydrolyzed Larix kraft pulp, where O1/O2 was two-stage oxygen delignification without interstage treatment, D was chlorine dioxide bleaching, EOP was pressurized alkaline extraction strengthened by hydrogen peroxide. Keeping bleaching temperature and time unchanged, sodium hydroxide charge(NaOH) in O1 stage, chlorine dioxide(ClO2) charge in D0 stage and D2 stage were studied, pulp properties such as brightness, kappa number, alpha-cellulose, pentosan and polymerization degree were measured and compared to establish optimal bleaching conditions. Results show that the optimal charge of NaOH in O1 stage is 2.5%, ClO2 in D0 and D2 stage are 2.5%, 0.6%, and the pulp gained at the optimal bleaching conditions has the properties of 93.9% of alpha-cellulose, 2.60% of pentosan, 375.5 ml/g of viscosity and 86.6%ISO of brightness.

scholarly journals Enzymes improve ECF bleaching of pulp

BioResources ◽  
2006 ◽  
Vol 1 (1) ◽  
pp. 34-44 ◽  
Keyword(s):  
Chlorine Dioxide ◽  
Acid Treatment ◽  
Kraft Pulp ◽  
Elemental Chlorine ◽  
Eucalyptus Kraft Pulp ◽  
Mediator System ◽  
Pulp Properties ◽  
Laccase Enzyme ◽  
Ecf Bleaching ◽  
Appreciable Reduction

The delignification efficiency of different laccase enzymes was examined on the eucalyptus Kraft pulp. The laccase enzyme from Trametes versicolor showing the highest delignification efficiency was selected and used in the elemental chlorine-free bleaching sequence for improving the pulp bleachability. A n appreciable reduction in chlorine dioxide consumption was also obtained. Further reduction in chlorine dioxide consumption was obtained when the same laccase treated pulp was subjected to an acid treatment after the extraction stage followed by the DE P D sequence. Elemental-chlorine free bleaching was also performed using the xylanase-laccase treated pulp. Xylanase treatment was incorporated to the laccase mediator system in the elemental-chlorine free bleaching both sequentially and simultaneously. The bleaching sequence DE P D followed and in both the cases, the reduction in chlorine dioxide consumption was greater in comparison to the control. The chlorine dioxide consumption was reduced further when xylanase-laccase treated pulp was given an additional acid treatment. The final pulp properties of the treated pulps were comparable to the control pulp.

scholarly journals Modification of chlorine dioxide bleaching of Gmelina arborea (gamar) pulp

2017 ◽  
Vol 52 (4) ◽  
pp. 247-252 ◽  
Author(s):  
M Sarwar Jahan ◽  
MM Uddin ◽  
MA Kashem
Keyword(s):  
Chlorine Dioxide ◽  
Kraft Pulp ◽  
Kappa Number ◽  
Side Reactions ◽  
Gmelina Arborea ◽  
Pulp Bleaching ◽  
Bleaching Process ◽  
Elemental Chlorine ◽  
Extraction Stage ◽  
Ecf Bleaching

Elemental Chlorine Free (ECF) pulp bleaching is now the dominant pulp bleaching process in globally. In most bleachery, chlorine dioxide is over-consumed. About two thirds of the chlorine dioxide is wasted in useless side reactions. In the study, kraft pulp from Gmelina arborea (gamar wood) was bleached by ECF bleaching in modified sequences. Oxygen prebleaching was carried out to decrease ClO2 requirement, which reduced kappa number of kraft pulp by 47.6% and increased pulp brightness by 21.7 percent points. Several sequences were tested based on the application of limited charges of ClO2 during successive ClO2and extraction stage. Application of this concept allowed a 33% reduction of ClO2 to reach target brightness. The kraft pulp could not reach target brightness of 80% in DED sequences using even 30 kg ClO2/ton of pulp, while splitting of same amount of ClO2 charge into DEDED sequences reached the pulp brightness to 81.1%. But oxygen delignified kaft pulp reached 79.6% brightness using 25 kg ClO2/ton of pulp in DED sequences. In the splitting of ClO2 charge into DEDED sequences, Oxygen pulp reached to 85% brightness by using only 20 kg ClO2/ton pulp.Bangladesh J. Sci. Ind. Res. 52(4), 247-252, 2017

scholarly journals Hydrogen peroxide bleaching of hardwood kraft pulp with adsorbed birch xylan and its effect on paper properties

BioResources ◽  
2011 ◽  
Vol 6 (1) ◽  
pp. 721-736
Author(s):  
Lizi Li ◽  
Sanghoon Lee ◽  
Hak Lae Lee ◽  
Hye Jung Youn
Keyword(s):  
Hydrogen Peroxide ◽  
Optical Properties ◽  
Kraft Pulp ◽  
Strength Properties ◽  
Pulp Fibers ◽  
Paper Properties ◽  
Peroxide Bleaching ◽  
Initial Ph ◽  
The Relationship ◽  
Temperature Time

The adsorption of xylan on pulp fibers improves the strength properties of paper. However, the optical properties are decreased significantly. The objective of our research was to bleach hardwood kraft pulp with adsorbed birch xylan by hydrogen peroxide and study the effect of bleaching parameters on paper properties. The bleaching parameters studied included bleaching temperature, time, initial pH as well as MgSO4 dosage. The optical properties (whiteness, brightness, opacity) and physical properties (tensile index, tearing index, bulk) of handsheets made from the pulp bleached with different process variables were measured. The results showed that better optical properties were obtained with higher bleaching temperature, longer bleaching time, and more MgSO4 dosage. Bleaching from an initial pH of 11 provided the highest brightness value. On the other hand, strength properties were improved with decreasing of the bleaching temperature, and increasing the initial pH and MgSO4 dosage. The relationship between strength properties and bleaching time varied depending on bleaching temperature. According to the results, both good mechanical properties and optical properties could be achieved when the operating parameters were controlled properly. Therefore hydrogen peroxide bleaching was proved to be a suitable method for bleaching hardwood kraft pulp with adsorption of birch xylan.

Recombinant manganese peroxidase (rMnP) from Pichia pastoris. Part 1: Kraft pulp delignification

Holzforschung ◽  
2010 ◽  
Vol 64 (2) ◽  
Author(s):  
Haowen Xu ◽  
Gary M. Scott ◽  
Fei Jiang ◽  
Christine Kelly
Keyword(s):  
Pichia Pastoris ◽  
Manganese Peroxidase ◽  
Lignin Content ◽  
Kappa Number ◽  
White Rot ◽  
Enzyme Treatment ◽  
High Yield ◽  
Kraft Pulps ◽  
Simultaneous Application ◽  
Peroxide Bleaching

AbstractManganese peroxidase (MnP) is the main enzyme implicated in the biobleaching of kraft pulps by white-rot fungi. However, potential commercial applications of this enzyme have been limited by its availability in large quantities. Advances have been made to produce high-yield concentrated recombinant MnP (rMnP). The objective of this study was to evaluate the ability of rMnP to delignify and brighten kraft pulps. The rMnP, produced from the yeastPichia pastoris– in high-cell density and in fed-batch fermentations – was found to be effective in lignin removal in both hardwood and softwood unbleached kraft pulps. The rMnP applied at 30 U g-1pulp for 24 h followed by alkali extraction caused significant kappa number reductions for all the pulps tested with different initial lignin contents and structures. Softwood and hardwood pulps showed similar delignification rates during rMnP treatments. Highly delignified pulps with kappa number less than 10 are less susceptible to delignification by rMnP compared with the pulps with higher lignin content. The rMnP-treated pulp was also shown to be more susceptible to subsequent peroxide bleaching compared with the control pulp. More than 60% of the kappa number reduction was achieved by sequential rMnP treatments combined with alkaline extraction. Sequential treatment with xylanase and rMnP also resulted in more extensive delignification than in each enzyme treatment alone or in the case of simultaneous application of the enzymes.

Alkaline peroxide treatment of ECF bleached softwood kraft pulps. Part 1. Characterizing the effect of alkaline peroxide treatment on carboxyl groups of fibers

Holzforschung ◽  
2007 ◽  
Vol 61 (4) ◽  
pp. 445-450 ◽  
Author(s):  
Zheng Dang ◽  
Thomas Elder ◽  
Arthur J. Ragauskas
Keyword(s):  
Carbonyl Group ◽  
Intrinsic Viscosity ◽  
Sodium Borohydride ◽  
Kraft Pulp ◽  
Carboxyl Groups ◽  
Kraft Pulps ◽  
Peroxide Bleaching ◽  
Bleached Kraft Pulp ◽  
Alkaline Peroxide ◽  
Group Content

Abstract The influence of alkaline peroxide treatment has been characterized on elementally chlorine-free (ECF) bleached softwood (SW) kraft pulp. The results indicate that fiber charge increased with an increase in peroxide charge: a maximum fiber charge increment of 16.6% was obtained with 8.0% more peroxide charge on oven-dried (o.d.) pulp at 60.0°C. Two primary bleaching temperatures of 60.0°C and 90.0°C were investigated during peroxide treatment. Copper number decreased for peroxide charges of 0.5% and 1.0% at 60.0°C and 90.0°C, respectively, then increased with increasing peroxide charge. Both fiber charge and copper number approached constant values when 4.0% or higher peroxide charge was applied. Peroxide treatment on a bleached kraft pulp at 90.0°C resulted in lower fiber charge and lower intrinsic viscosity compared to treatment at 60.0°C. Sodium borohydride (NaBH4) pretreatment was able to protect the fibers from being degraded during peroxide bleaching. Fiber charge and copper number were compared after peroxide treatment of ECF bleached kraft pulp to NaBH4-reduced ECF bleached kraft pulp. The results indicate that the carbonyl group content of fibers is favorable for improving fiber charge after peroxide treatment.

scholarly journals EFFECT OF RECYCLING OF ELEMENTAL CHLORINE FREE BLEACHING EFFLUENT TREATED BY ELECTROCOAGULATION ON PAPER PROPERTIES

2021 ◽  
Vol 55 (7-8) ◽  
pp. 809-819
Author(s):  
QASEEM HAIDER ◽  
DUSHYANT KUMAR ◽  
CHHAYA SHARMA
Keyword(s):  
Current Density ◽  
Pollution Control ◽  
Treatment Time ◽  
Oxygen Demand ◽  
Strength Properties ◽  
Optimum Conditions ◽  
Paper Properties ◽  
Elemental Chlorine ◽  
Maximum Decrease ◽  
Ecf Bleaching

This study aimed to determine the effect of recycling elemental chlorine free (ECF) bleaching effluent (D0EpD1 and OD0EpD1) after treatment through electrocoagulation under optimum conditions on paper properties. The effect of pH, current density, time and dose of electrolyte on the reduction of chemical oxygen demand (COD) and color was studied. Maximum decrease in COD and color was found under optimum conditions (i.e., pH 7, treatment time of 30 min, current density of 29.16 mA/cm2, and 1 g/L NaCl). Under these optimum conditions, the reduction in COD and color was of 79.9% and 99.10%, respectively. The reduction in the strength properties of paper, caused by recycling, was found to be insignificant, but a decline of 2.11% for D0EpD1 and of 1.43% for OD0EpD1 in brightness was found. Using the electrocoagulation method to treat the bleaching effluent can prove to have valuable potential towards wastewater utilization, pollution control, and sustainable development of the industry.

Pilot trials of hemicelluloses extraction prior to thermomechanical pulp production: Part 1

TAPPI Journal ◽  
2011 ◽  
Vol 10 (5) ◽  
pp. 21-28 ◽  
Author(s):  
CARL HOUTMAN ◽  
ERIC HORN
Keyword(s):  
Oxalic Acid ◽  
Energy Savings ◽  
Wood Chip ◽  
Strength Properties ◽  
Thermomechanical Pulp ◽  
Sugar Solution ◽  
Bisulfite Treatment ◽  
Pilot Trials ◽  
Pulp Production ◽  
Production Part

Pilot data indicate that wood chip pretreatment with oxalic acid reduced the specific energy required to make thermomechanical pulp. A combined oxalic acid/bisulfite treatment resulted in 21% refiner energy savings and 13% increase in brightness for aspen. A low level of oxalic acid treatment was effective for spruce. Energy savings of 30% was observed with no significant change in strength properties. Adding bisulfite did not significantly increase the brightness of the spruce pulp. For pine, the optimum treatment was a moderate level of oxalic acid, which resulted in 34% energy savings and an increase in strength properties. For all of these treatments 1–3 w/w % carbohydrates were recovered, which can be fermented to produce ethanol. The extract sugar solution contained significant quantities of arabinose.

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