Studies on Xylanase and Laccase Enzymatic Prebleaching to Reduce Chlorine-Based Chemicals During Ceh and Ecf Bleaching

Thakur, Vasanta Vadde; Jain, Rakesh; Mathur, R. M.

doi:10.15376/biores.7.2.2220-2235

Cited by 38 publications

(22 citation statements)

References 11 publications

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“…These observations on the reduction in kappa number by xylanase were also supported by Thakur et al (2012), wherein Pulpzyme HC was used and a 4.2% reduction in kappa number of eucalyptus pulp was achieved. Brightness gains of 2.4, 2.7, and 2.9 units were obtained in acacia wood pulp, while brightness gains of 2.3, 2.4, and 2.8 units were observed in eucalyptus pulp at enzyme doses of 0.1, 0.3, and 0.5 kg/tp, respectively, compared with the control (Table 2).…”

Section: Resultssupporting

confidence: 58%

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Amenability of Acacia and Eucalyptus Hardwood Pulps to Elemental Chlorine-Free Bleaching: Application and Efficacy of Microbial Xylanase

Gangwar¹,

Prakash²,

Prakash³

2015

BioResources

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This study outlines the results of a biobleaching study of acacia (A. mangium) and eucalyptus (E. globulus) hardwood kraft pulps with commercial xylanase (Optimase CX 72 L). The comparative study was carried out using an elemental chlorine-free (ECF) bleaching sequence (D0EPD1D2) after the enzyme (X) stage. The enzyme treatment resulted in improved optical properties with a reduction in bleach chemical consumption. At an equivalent bleach chemical consumption, a brightness gain of 2.1 and 1.7 units and a whiteness gain of 2.7 and 2.3 units were observed with xylanase treatment in acacia and eucalyptus pulps, respectively. In ECF bleaching using the D0EPD1D2 sequence, a final brightness was achieved to the extent of 90% ISO and 89% ISO for acacia and eucalyptus, respectively, at an equivalent charge of bleach chemicals. The post-color (PC) number was also reduced by up to 45% for both hardwood pulps compared with the control. The bleachability of acacia was observed to be significantly higher than that of eucalyptus. In addition, a 17.0% and 23.0% reduction in chlorine dioxide and sodium hydroxide, respectively, were obtained for both hardwood pulps after xylanase pre-bleaching, thus indicating an environmentally friendly approach to the process.

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Section: Resultssupporting

confidence: 58%

“…In addition, a key reduction was seen in the consumption of chlorine dioxide and sodium hydroxide in ECF bleaching, as shown in Table 3. A reduction in chlorine dioxide of 14.3% was also reported in the eucalyptus pulp during enzymatic bleaching (Thakur et al 2012).…”

Section: Resultsmentioning

confidence: 60%

Amenability of Acacia and Eucalyptus Hardwood Pulps to Elemental Chlorine-Free Bleaching: Application and Efficacy of Microbial Xylanase

Gangwar¹,

Prakash²,

Prakash³

2015

BioResources

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“…Overall, xylanase treatments were promising and showed reduction in COD and BOD levels in combined bleaching effluents for each sequence versus the respective controls. Other investigators have also reported that xylanase bleaching led to a reduction in AOX found in bleaching filtrates and to an appreciably higher BOD-to-COD ratio for the xylanase prebleaching filtrates (Senior and Hamilton 1991;Bajpai 2010;Thakur et al 2012;Gangwar et al 2014).…”

Section: Resultsmentioning

confidence: 91%

An Eco-Friendly Approach: Incorporating a Xylanase Stage at Various Places in ECF and Chlorine-based Bleaching of Eucalyptus Pulp

Gangwar

Prakash

2016

BioResources

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A potentially more environmentally compatible approach was evaluated, involving the use of an enzyme (X) stage optimally inserted into various bleaching sequences for Eucalyptus kraft pulps. The efficacy of the X stage was evaluated in terms of final brightness, CIE whiteness, post-color number (brightness reversion), effluent characteristics, etc. The results showed considerable benefits with an enzymatic pre-treatment bleaching sequence for improved final pulp brightness (1.6 units higher) and reduced adsorbable organic halogens (AOX) (32% lower), in addition to improved biological oxygen demand (BOD) to chemical oxygen demand (COD) ratio, when using 0.5 kg/t pulp dosage of xylanase; enzymatic posttreatment bleaching sequences were observed to boost final CIE whiteness up to 3.4 units and to reduce post color number by 48% at 0.5 kg/t pulp dosage of xylanase. In addition, approximately 32% reductions in AOX released, as well as appreciable improvement in BOD-to-COD ratio, were observed in the bleach effluents. An improved ratio of BOD-to-COD facilitates possible enhancement in the bio-degradability of discharge effluents in a secondary treatment stage. Nine different bleaching sequences were compared. Three sequences for each category (pre-treatment, intermediate, and post-treatment bleaching sequences) were performed to provide an overview of the influence of xylanase treatment on various pulp properties and environmental sum parameters of the ensuing effluents.

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“…The results of the analysis of whiteness are shown in (Valls and Roncero 2009;Thakur et al 2012;Sharma et al 2014), thus the increase of whiteness may be due to the bleaching effect of the enzyme.…”

Section: Measurement Of Whiteness Of the Mow Pulp Treated With Laccasmentioning

confidence: 99%

Laccase based de-inking of mixed office waste and evaluation of its impact on physico-optical properties of recycled fiber

Shankar

Shikha

Bhan

et al. 2018

Environmental Sustainability

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The de-inking ability of the crude laccase (benzenediol: oxygen oxidoreductase, EC 1.10.3.2) produced by a white rot fungus Peniophora sp. (NFCCI-2131) was tested using mixed office waste paper. In addition, the impact on physical and optical properties of the de-inked pulp, and the chemical load of the effluent generated during laccase based de-inking process was also analyzed. In the present study, 2.5 U/ml laccase was produced by the fungus under submerged culture conditions. Laccase (10 U/g of air dried pulp) was found to improve the tensile strength of recycled pulp by 1.7-fold, de-inking efficiency by 1.5-fold, opacity by 3.84%, and brightness by 5.83%. Scanning electron microscopy analysis revealed less rupturing of cellulose fibers and increased detachment of ink particles from the surface of the fibers in comparison to chemical de-inking. Fourier-transform infrared spectroscopy analysis of laccase treated pulp revealed degradation of the guaiacyl group and a high degree of deformation in methyl group of lignin. The biochemical and chemical oxygen demand (BOD and COD) were found to be reduced by 52 and 36% respectively, in the effluent generated after crude laccase based de-inking of mixed office waste.

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Studies on Xylanase and Laccase Enzymatic Prebleaching to Reduce Chlorine-Based Chemicals During Ceh and Ecf Bleaching

Cited by 38 publications

References 11 publications

Amenability of Acacia and Eucalyptus Hardwood Pulps to Elemental Chlorine-Free Bleaching: Application and Efficacy of Microbial Xylanase

Amenability of Acacia and Eucalyptus Hardwood Pulps to Elemental Chlorine-Free Bleaching: Application and Efficacy of Microbial Xylanase

An Eco-Friendly Approach: Incorporating a Xylanase Stage at Various Places in ECF and Chlorine-based Bleaching of Eucalyptus Pulp

Laccase based de-inking of mixed office waste and evaluation of its impact on physico-optical properties of recycled fiber

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