{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,4,9]],"date-time":"2026-04-09T11:00:09Z","timestamp":1775732409571,"version":"3.50.1"},"reference-count":27,"publisher":"MDPI AG","issue":"21","license":[{"start":{"date-parts":[[2022,11,3]],"date-time":"2022-11-03T00:00:00Z","timestamp":1667433600000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"Bio-based Industries Joint Undertaking (BBI JU)","award":["GA 792070"],"award-info":[{"award-number":["GA 792070"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["IJMS"],"abstract":"<jats:p>Xylanases can boost pulp bleachability in Elemental Chlorine Free (ECF) processes, but their industrial implementation for producing bleached kraft pulps is not straightforward. It requires enzymes to be active and stable at the extreme conditions of alkalinity and high temperature typical of this industrial process; most commercial enzymes are unable to withstand these conditions. In this work, a novel highly thermo and alkaline-tolerant xylanase from Pseudothermotoga thermarum was overproduced in E. coli and tested as a bleaching booster of hardwood kraft pulps to save chlorine dioxide (ClO2) during ECF bleaching. The extremozyme-stage (EXZ) was carried out at 90 \u00b0C and pH 10.5 and optimised at lab scale on an industrial oxygen-delignified eucalyptus pulp, enabling us to save 15% ClO2 to reach the mill brightness, and with no detrimental effect on paper properties. Then, the EXZ-assisted bleaching sequence was validated at pilot scale under industrial conditions, achieving 25% ClO2 savings and reducing the generation of organochlorinated compounds (AOX) by 18%, while maintaining pulp quality and papermaking properties. Technology reproducibility was confirmed with another industrial kraft pulp from a mix of hardwoods. The new enzymatic technology constitutes a realistic step towards environmentally friendly production of kraft pulps through industrial integration of biotechnology.<\/jats:p>","DOI":"10.3390\/ijms232113423","type":"journal-article","created":{"date-parts":[[2022,11,3]],"date-time":"2022-11-03T03:53:07Z","timestamp":1667447587000},"page":"13423","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":12,"title":["Use of a Novel Extremophilic Xylanase for an Environmentally Friendly Industrial Bleaching of Kraft Pulps"],"prefix":"10.3390","volume":"23","author":[{"given":"Nazar\u00e9","family":"Almeida","sequence":"first","affiliation":[{"name":"RAIZ\u2014Forest and Paper Research Institute, Rua Jos\u00e9 Estev\u00e3o 221, Eixo, 3800-783 Aveiro, Portugal"}]},{"given":"Val\u00e9rie","family":"Meyer","sequence":"additional","affiliation":[{"name":"Centre Technique du Papier\u2014The French Pulp and Paper Technical Centre, Domaine Universitaire, CS90251, CEDEX 9, 38044 Grenoble, France"}]},{"given":"Auph\u00e9lia","family":"Burnet","sequence":"additional","affiliation":[{"name":"Centre Technique du Papier\u2014The French Pulp and Paper Technical Centre, Domaine Universitaire, CS90251, CEDEX 9, 38044 Grenoble, France"}]},{"given":"Jeremy","family":"Boucher","sequence":"additional","affiliation":[{"name":"Fibre Excellence Saint-Gaudens\u2014Rue du President Saragat, 31800 Saint-Gaudens, France"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-8693-4239","authenticated-orcid":false,"given":"David","family":"Talens-Perales","sequence":"additional","affiliation":[{"name":"Instituto de Agroqu\u00edmica y Tecnolog\u00eda de Alimentos, CSIC Agust\u00edn Escardino 7, 46980 Paterna, Valencia, Spain"}]},{"given":"Susana","family":"Pereira","sequence":"additional","affiliation":[{"name":"RAIZ\u2014Forest and Paper Research Institute, Rua Jos\u00e9 Estev\u00e3o 221, Eixo, 3800-783 Aveiro, Portugal"}]},{"given":"Petri","family":"Ihalainen","sequence":"additional","affiliation":[{"name":"MetGen Oy, Rakentajantie 26, 20780 Kaarina, Finland"}]},{"given":"Thomas","family":"Lev\u00e9e","sequence":"additional","affiliation":[{"name":"MetGen Oy, Rakentajantie 26, 20780 Kaarina, Finland"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-9912-0640","authenticated-orcid":false,"given":"Julio","family":"Polaina","sequence":"additional","affiliation":[{"name":"Instituto de Agroqu\u00edmica y Tecnolog\u00eda de Alimentos, CSIC Agust\u00edn Escardino 7, 46980 Paterna, Valencia, Spain"}]},{"given":"Michel","family":"Petit-Conil","sequence":"additional","affiliation":[{"name":"Centre Technique du Papier\u2014The French Pulp and Paper Technical Centre, Domaine Universitaire, CS90251, CEDEX 9, 38044 Grenoble, France"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-2812-895X","authenticated-orcid":false,"given":"Susana","family":"Camarero","sequence":"additional","affiliation":[{"name":"Centro de Investigaciones Biol\u00f3gicas Margarita Salas, CSIC, Ramiro de Maeztu 9, 28040 Madrid, Spain"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-1561-4406","authenticated-orcid":false,"given":"Paula","family":"Pinto","sequence":"additional","affiliation":[{"name":"RAIZ\u2014Forest and Paper Research Institute, Rua Jos\u00e9 Estev\u00e3o 221, Eixo, 3800-783 Aveiro, Portugal"}]}],"member":"1968","published-online":{"date-parts":[[2022,11,3]]},"reference":[{"key":"ref_1","first-page":"67","article-title":"Efficient enzymatic delignification of wheat straw pulp by a sequential xylanase-laccase mediator treatment","volume":"28","author":"Jeller","year":"2002","journal-title":"J. Pulp Pap. Sci."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"45","DOI":"10.1016\/S0032-9592(00)00178-3","article-title":"Effects of xylanase treatment on fibre morphology in totally chlorine free bleaching (TCF) of Eucalyptus pulp","volume":"36","author":"Roncero","year":"2000","journal-title":"Process Biochem."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"1023","DOI":"10.1002\/jctb.893","article-title":"Effect of xylanase on ozone bleaching kinetics and properties of Eucalyptus kraft pulp","volume":"78","author":"Roncero","year":"2003","journal-title":"J. Chem. Technol. Biotechnol."},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"21","DOI":"10.1016\/j.biortech.2004.03.003","article-title":"The effect of xylanase on lignocellulosic components during the bleaching of wood pulps","volume":"96","author":"Roncero","year":"2005","journal-title":"Bioresour. Technol."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"147","DOI":"10.1021\/bp990013k","article-title":"Application of Enzymes in the Pulp and Paper Industry","volume":"15","author":"Bajpai","year":"1999","journal-title":"Biotechnol. Prog."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"22","DOI":"10.1016\/j.biombioe.2018.12.014","article-title":"Biobleaching of Kraft pulp using fungal xylanases produced from sugarcane straw and the subsequent decrease of chlorine consumption","volume":"121","author":"Campioni","year":"2019","journal-title":"Biomass Bioenergy"},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"101604","DOI":"10.1016\/j.bcab.2020.101604","article-title":"Greener approach for pulp and paper industry by Xylanase and Laccase","volume":"25","author":"Sharma","year":"2020","journal-title":"Biocatal. Agric. Biotechnol."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"2032","DOI":"10.1016\/j.biortech.2008.10.009","article-title":"Using both xylanase and laccase enzymes for pulp bleaching","volume":"100","author":"Valls","year":"2009","journal-title":"Bioresour. Technol."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"318","DOI":"10.1515\/hfsg.1993.47.4.318","article-title":"Proposed Mechanism of the Enzymatic Bleaching of Kraft Pulp with Xylanases","volume":"47","author":"Kantelinen","year":"1993","journal-title":"Holzforschung"},{"key":"ref_10","first-page":"62","article-title":"Microbial Xylanase: An Eco-friendly Tool for Bleaching of Lignocellulosic Paper Pulp","volume":"2","author":"Dukare","year":"2021","journal-title":"Vigyan Varta"},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"2676","DOI":"10.1016\/j.csbj.2021.05.004","article-title":"Phylogenetic, functional and structural characterization of a GH10 xylanase active at extreme conditions of temperature and alkalinity","volume":"19","author":"Polaina","year":"2021","journal-title":"Comput. Struct. Biotechnol. J."},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"144","DOI":"10.1016\/j.nbt.2017.05.002","article-title":"Towards a sustainable biobased industry\u2013Highlighting the impact of extremophiles","volume":"40","author":"Antranikian","year":"2018","journal-title":"New Biotechnol."},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"10137","DOI":"10.1038\/s41598-019-46290-w","article-title":"GeneHunt for rapid domain-specific annotation of glycoside hydrolases","volume":"9","author":"Nguyen","year":"2019","journal-title":"Sci. Rep."},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"198","DOI":"10.1186\/s13068-020-01842-5","article-title":"In silico screening and experimental analysis of family GH11 xylanases for applications under conditions of alkaline pH and high temperature","volume":"13","author":"Polaina","year":"2020","journal-title":"Biotechnol. Biofuels"},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"113","DOI":"10.2166\/wst.1991.0468","article-title":"The Anaerobic Biodegradability and Methanogenic Toxicity of Pulping Wastewaters","volume":"24","author":"Kortekaas","year":"1991","journal-title":"Water Sci. Technol."},{"key":"ref_16","doi-asserted-by":"crossref","unstructured":"Mehmood, K., Rehman, S.K.U., Wang, J., Farooq, F., Mahmood, Q., Jadoon, A.M., Javed, M.F., and Ahmad, I. (2019). Treatment of Pulp and Paper Industrial Effluent Using Physicochemical Process for Recycling. Water, 11.","DOI":"10.3390\/w11112393"},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"9150","DOI":"10.1016\/j.biortech.2010.07.020","article-title":"Application of cellulase-free xylano-pectinolytic enzymes from the same bacterial isolate in biobleaching of kraft pulp","volume":"101","author":"Kaur","year":"2010","journal-title":"Bioresour. Technol."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"255","DOI":"10.1007\/s12010-009-8654-4","article-title":"Bleach Enhancement of Mixed Wood Pulp by Xylanase\u2013Laccase Concoction Derived Through Co-culture Strategy","volume":"160","author":"Dwivedi","year":"2009","journal-title":"Appl. Biochem. Biotechnol."},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"96","DOI":"10.1016\/j.biortech.2014.06.066","article-title":"Xylanase and laccase based enzymatic kraft pulp bleaching reduces adsorbable organic halogen (AOX) in bleach effluents: A pilot scale study","volume":"169","author":"Sharma","year":"2014","journal-title":"Bioresour. Technol."},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"2513","DOI":"10.1007\/s00449-021-02623-6","article-title":"Xylanolytic enzyme consortia from Bacillus sp. NIORKP76 for improved biobleaching of kraft pulp","volume":"44","author":"Parab","year":"2021","journal-title":"Bioprocess Biosyst. Eng."},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"459","DOI":"10.1016\/S0141-0229(00)00231-3","article-title":"Enhanced production of a thermostable xylanase from Streptomyces sp. QG-11-3 and its application in biobleaching of eucalyptus kraft pulp","volume":"27","author":"Beg","year":"2000","journal-title":"Enzym. Microb. Technol."},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"139","DOI":"10.1023\/A:1023244911314","article-title":"Application of crude xylanase from Bacillus licheniformis 77-2 to the bleaching of eucalyptus Kraft pulp","volume":"19","author":"Damiano","year":"2003","journal-title":"World J. Microbiol. Biotechnol."},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"273","DOI":"10.1016\/S0960-8524(99)00116-9","article-title":"A cellulase-poor, thermostable, alkalitolerant xylanase produced by _Bacillus_ _circulans_ AB 16 grown on rice straw and its application in biobleaching of eucalyptus pulp","volume":"73","author":"Dhillon","year":"2000","journal-title":"Bioresour. Technol."},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"65","DOI":"10.1007\/s00253-005-0036-4","article-title":"Biobleach boosting effect of recombinant xylanase B from the hyperthermophilic Thermotoga maritima on wheat straw pulp","volume":"70","author":"Jiang","year":"2005","journal-title":"Appl. Microbiol. Biotechnol."},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"1373","DOI":"10.1007\/s10295-013-1347-6","article-title":"Improvement in thermostability of metagenomic GH11 endoxylanase (Mxyl) by site-directed mutagenesis and its applicability in paper pulp bleaching process","volume":"40","author":"Satyanarayana","year":"2013","journal-title":"J. Ind. Microbiol. Biotechnol."},{"key":"ref_26","unstructured":"Birikh, K.R., Heikkila, M.W., Michine, A., Mialon, A., Gr\u00f6nroos, T., Ihalainen, P., Varho, A., H\u00e4m\u00e4l\u00e4inen, V., Suonp\u00e4\u00e4, A., and Rantanen, S.-P. (2018). CHAPTER 11 MetGen: Value from Wood\u2013Enzymatic Solutions. Biocatal: An Ind Perspect, The Royal Society of Chemistry."},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"1073","DOI":"10.1007\/s10570-016-0881-6","article-title":"Comparison of sample crystallinity determination methods by X-ray diffraction for challenging cellulose I materials","volume":"23","author":"Ahvenainen","year":"2016","journal-title":"Cellulose"}],"container-title":["International Journal of Molecular Sciences"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/1422-0067\/23\/21\/13423\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T01:09:43Z","timestamp":1760144983000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/1422-0067\/23\/21\/13423"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2022,11,3]]},"references-count":27,"journal-issue":{"issue":"21","published-online":{"date-parts":[[2022,11]]}},"alternative-id":["ijms232113423"],"URL":"https:\/\/doi.org\/10.3390\/ijms232113423","relation":{},"ISSN":["1422-0067"],"issn-type":[{"value":"1422-0067","type":"electronic"}],"subject":[],"published":{"date-parts":[[2022,11,3]]}}}