色色啦

Department of Bioproducts and Biosystems

Wood Extractives

The Wood Extractives group is headed by Academy Research Fellow Jinze Dou. The group鈥檚 research interests focus on fundamental understanding of the challenges posed by wood extractives, particularly in the areas of the wood yard and the fiber line of pulp mills, including pre-treatment techniques for 鈥減ulping鈥 of the bark, characterization and (bio)chemical control of pitch/stickies deposits, and the functionalization of extractives for added-value biochemicals.
Color photo of a hat made of fine bark strips featuring a red hatband and a fiber-constructed letter "A"
Handcraft: Tapani Vuorinen, Photo: Valeria Azovskaya | Aalto University

Research topics

  • Bark structure and chemistry
  • Role of the extractives in formation of pitch/stickies deposits
  • Extractives functionalization
Wood fibers
Photo: Valeria Azovskaya | Aalto University

Ongoing research projects

Effect of Fiberline on Chemical Transformation of Wood Extractives- Reaction Mechanism and Recovery (BE-Stilbene)
Buildup of the secondary-form wood extractives decreases the pulp mill鈥檚 productivity as they partly form different carry-over pitch (or scale) components at the fiberline, leading to excessive chemical consumption. The native-form wood extractives (prior to the fiberline) have been well researched for decades, but there is not enough scientific data to investigate the reaction mechanisms behind its secondary form (in the fiberline). Industrial-scale separation / recovery process, however, is largely dependent on the reaction mechanisms that occur throughout the fiberline. If we want to utilize them in future biorefineries, we need to know how they react in the fiberline and where they can be recovered (in the form having their maximum commercial value) before being chemically spoiled (or reacted). CIMANET project BE-Stilbene is designed to find ways to gain essential knowledge of the reactions (such as degradation, oxidation or formation of newly secondary products) between the wood extractives and cooking (kraft and sulfite)/ bleaching chemicals.

Related publication:
Dou, J.*; Sui, M.; Malinen, K.; Pesonen, T.; Isohanni, T.; Vuorinen, T. Spruce Bark Stilbenes as a Nature-inspired Sun Blocker for Sunscreens. (2022-03-02) Green Chem. 24, 2962鈭2974. .

Pitch deposits in the bleach plant process pipe
Pitch deposits in the bleach plant process pipe. Photo: Jinze Dou

Understanding the Role of Wood Extractives in Formation of Pitch Deposits (WEPitch)
Control of wood extractives has a vital role in closing the water loops in pulp mills, thus helping the pulp and paper industry to achieve the 鈥渮ero effluent鈥 target. As there is no efficient way to control and remove them from the fiber line, extractives can be a technical challenge. Wood extractives cause a lot of effort to the process and can create serious problems, because they flow and accumulate in water, forming pitch deposits. The extractives retained in the pulps may adversely affect the physiochemical properties of the products. Efficient removal of pitch deposits from the fiber line is currently hampered by the lack of knowledge of their full chemical characteristics and the exact formation mechanism. The Industry- and FinnCERES- jointly funded project WEPitch (2024-2028) is designed to find ways to gain essential knowledge to understand, prevent and control deposit formation and improve the overall operation, revenue and quality performance of the pulp and paper mill.

Related publication:
Dou, J.*; Niemel盲, Klaus*; Haatainen, Tiina; Tervola, Pekka; Vehmaa Janne*. Investigation of pitch deposits throughout the fibre line of softwood pulp mills. (2023-03-28) J. Cleaner Prod. 405, 136940. https://doi.org/10.1016/j.jclepro.2023.136940.

Color photograph of a person in the forest wearing a lab coat and blue gloves pouring brown liquid from a glass tube into a glass flask, next to a container of bark/wood chips and a brown liquid being filtered into another glass flask
Photo: Eeva Suorlahti | Aalto University CHEMARTS

Stability enhancement of softwood (sawdust wood and bark) stilbene through chemical functionalization as ultra stable UV-filters in sunscreen (FACE+)

Trans-stilbenes can be isomerized to their cis-isomers under sunlight, and the cis-isomers are prone to undergo a Mallory reaction yielding polycyclic aromatic hydrocarbons. This preference is very hard to overcome as it is strictly under orbital symmetry control. The Academy of Finland Research Fellow project (2023鈥2027) will focus on functionalizing the recovered stilbene from pine wood sawdust and spruce bark as ultra-stable UV-filter alternatives for sunscreen. This may improve the stilbene stability 1000-fold without losing its UV-absorbing activity. These materials are today merely burned for energy, but when using them to added-value chemicals, it could allow more incomes for the Finnish forest owners and industry.

Related publications:

Dou, J.*; Multia, Evgen; Dong, Xinyue; Wang, Lei*; Vuorinen, Tapani. Valorization of long-neglected spruce bark and bark-press effluents through integrated utilization of stilbenoids and pectin. (2023) Chem. Eng. J. .

News

  • Leskinen Lauri joins the group for WEPitch project in March 2025
  • Lempinen Mery joins the group for Master thesis project in March 2025
  • Purola Annika joins the group for Bachelor thesis project in February 2025
  • Wu Yue joins the group under The Ministry of Education and Culture (CIMANET) funded project BE-Stilbene in January 2025
  • Leskinen Lauri and Ouyang Kun join the group for Master thesis project in September 2024
  • Levan Simo joins the group for Bachelor thesis project in September 2024
  • New CIMANET project "BE-Stilbene" launched in September 2024
  • Melnik Elena joins the lab in June 2024
  • Xi Hao and Ali Muhammad join the lab for master thesis project in February 2024
  • Karvonen Noora, Heikkil盲 Mitja, and Haag Vera join the lab for bachelor thesis project in Jan 2024
  • New project "WEPitch", jointly funded by Industry and FinnCERES, started in March 2024
  • Munib Wajeeha joins the lab in December 2023
  • New project "FACE+", funded by Academy of Finland, started in September 2023

Teaching

Dr. Dou teaches the course 鈥淐HEM-LV04 - Analytics in Wood Chemistry (5 ECTS)鈥, organized next time at May 2025. The target of the course is to give a comprehensive overview of analytical methods to doctoral students for chemical characterization of non-cellulose wood components. Particularly, the students are expected to have a basic understanding of the chemistry of wood (chemical structure) in relation to their isolation/ purification protocols. Also, Dr. Dou teaches 鈥淐HEM-E1210 - Bioproduct Mill Recovery Processes (5 ECTS)鈥 next time at October 2025. Dou also gives the lecture 鈥樷榃ood Extractives in Fiberline鈥欌 as part of the course 鈥樷楥HEM-E1150 - Biomass Pretreatment and Fractionation鈥欌. The main target of the lecture is to focus on the reactivity of wood extractives in fiberline.

Alumni

Name Role Title of thesis Year(s) Current location
Hao Xi M.Sc. Effect of Bleaching on the Transformation of Wood Stilbenes 2024  
Muhammad Ali M.Sc. Understanding of the Non-cellulosic Components in Deinked Pulp  2024  

Previous research project

Fractionation of willow bark for combined production of extracts and fiber bundles

Color photo of willow tree bark
Photo: Aalto University

This project, mainly funded by Finnish Cultural Foundation (2016-2019) and FinnCERES (2019-2021), provides a general, integrative study on the morphology and chemistry of willow wood and bark and its fractionation into hot water extract, fiber bundles, fibers and fibrils. Potentially interesting research approaches and gaps in our current knowledge are identified and discussed on the way towards full exploitation of the value of the bark as a source fibers and extracts.

Related publications

Dou, J.*; Wang, Jincheng; Hietala, Sami; Vuorinen, Tapani*; Zhao, Jian. Structural Features of Lignin-Hemicellulose-Pectin (LHP) Orchestrate the Tailored Microbial Consortium for potential in Bark Biorefinery. (2023) Green Chem. .

Dou, J.*; K枚gler, Martin; Kesari, Kavindra; Pitk盲nen, Leena; Vuorinen, Tapani. Seasonal dynamics in structural characteristics within bark stems of cultivated willow (Salix sp.) by NMR and time-gated Raman spectroscopy. (2023-01-26) Green Chem. 25, 1908鈭1919. .

Dou, J.*; Wang, J.; Zhao, J.*; Vuorinen, T. Tailor-made Enzyme Consortium Segregating Sclerenchyma Fibre Bundles from Willow Bark. (2022-02-23) Green Chem. 24, 2576鈭2587. .

Dou, J.*; Chandgude, V.; Vuorinen, T.*; Bankar, S.; Hietala, S.; Huy, L. Enhancing Biobutanol Production from Biomass Willow by Pre-removal of Water Extracts or Bark. (2021-10-22) J. Cleaner Prod.327, 129432. .

Dou, J.*; Heinonen, J.; Xu, C.; Vuorinen, T.; Sainio, T.* Chromatographic purification of the natural phytochemicals from willow bark water extracts. (2020-12-26) Sep. Purif. Technol. 261, 118247..

Dou, J.; Kim, H.; Li, Y.; Padmakshan, D.; Yue, F.; Ralph J.; Vuorinen, T*. Structural characterization of lignins from willow bark and wood. (2018-06-22) J. Agric. Food Chem. 66, 7294鈭7300. .

Dou, J.; Galvis, L.; Holopainen-Mantila, U.; Reza, M.; Tamminen, T.; Vuorinen, T*. Morphology and Overall Chemical Characterization of Willow (Salix sp.) Inner Bark and Wood: Toward Controlled Deconstruction of Willow Biomass. (2016-06-06) ACS Sustainable Chem. Eng. 4, 3871鈥3876. .

Group members

 Jinze Dou

Jinze Dou

Academy Research Fellow

Elena Melnik

Doctoral Researcher

Kun Ouyang

Master's Thesis Worker

Lauri Leskinen

Research Assistant
Academy Research Fellow Jinze Dou.

Research Council of Finland Fellow Dr. Jinze Dou

Dr. Dou obtained his PhD in the field of Bioproduct Technology under the supervision of Prof. Tapani Vuorinen from Aalto University in 2018, though part of his research was carried out at the University of Wisconsin Madison, USA, under the supervision of Prof. John Ralph. During his postdoctoral research work at Aalto, he had long visits to the University of Aveiro, Portugal (Prof. Dmitry Evtyuguin), Lappeenranta-Lahti University of Technology in Finland (Prof. Tuomo Sainio) and Shandong University, China (Prof. Jian Zhao). In addition to these academic steps, he also has industrial experience working as a research scientist at Andritz Oy (January 2022-August 2023). The Research Council of Finland (formerly known as the Academy of Finland) awarded Dou the Academy Research Fellowship for 2023-2027.

Munib Wajeeha

Doctoral Researcher Wajeeha Munib

Munib is a doctoral student specializing in the stability enhancement of stilbenes from pine wood sawdust and spruce bark through chemical functionalization. She has a foundational Master's degree in organic chemistry and a robust research background in organic synthesis. Her current doctoral research is focused on developing ultra-stable UV filters for sunscreen applications, leveraging the inherent properties of softwood sawdust and spruce bark extractive stilbenes. Areas of interest include: wood extractives, controlled stereo chemical reactions, and chemical functionalization of stilbenes for macrocyclization. 

Elena wearing glasses and a red sweater.

Doctoral Researcher Elena Melnik

Elena is a doctoral researcher working on understanding the role of wood extractives in the pulp and paper industry, particularly using eucalyptus wood as a primary resource. Her research investigates the chemical composition of extractives and their transformation into pitch deposits, a significant issue in industrial processing. By understanding the pathways that lead to pitch formation, this research aims to contribute to more sustainable and efficient production processes. Elena鈥檚 previous academic background has provided a strong foundation in organic and analytical chemistry, with a specialization in separation methods in complex organic matrices. Areas of interest include wood chemistry, industrial process optimization, and advancing sustainable practices in the industry, with a focus on reducing environmental impact.

A black and white photo of Kun wearing glasses and a T-shirt.

Master's Thesis Worker Kun Ouyang

Kun is a master's student at Aalto University, specializing in biomass refining. Under the supervision of Dr. Jinze Dou, he is currently conducting research for his master鈥檚 thesis on "Pulping and Bleaching of Bagasse". With a solid background in bio-based materials and pulping, and a bachelor's degree in the field, Kun is highly motivated to apply these technologies in industrial applications to conserve resources and improve the environment.

Yue wearing a black crewneck on a white background

Doctoral Researcher Yue Wu

Wu is a doctoral student having background on pulping and bleaching technology. His research aims to orchestrate a tailored recovery strategy of wood extractives in the fiberline by understanding the underlying reaction mechanisms that occur at cooking and bleaching process. Areas of interest include the reaction mechanism of wood extractives in the ECF bleaching process, recovery process and analytical characterization of its products.

Lauri's front profile

Research Assistant Lauri Leskinen

Lauri is a research assistant working to develop analytical methodologies for analysing fiber line samples with an emphasis on wood extractives. He has built a solid foundation of skills in analytical chemistry and a wide knowledge of fiber line processes throughout his studies and working experience. Extensive knowledge of wood extractives and their dissolution characteristics are key tools for solving pitch deposition problems which are a major concern in the pulping industry. 

Latest publications

Jinze Dou, Adedayo Bello, Jari Koivisto, Kristoffer Meinander, Tiina Leivisk盲, Tapani Vuorinen 2024 Industrial Crops and Products

Pirjo K盲盲ri盲inen, Susanna Ahola, Tapani Vuorinen, Janika Lehtonen, Greta Salonen, Jinze Dou, Iines Jakovlev, Satu Paavonsalo, Nina Riutta, Elizaveta Tapaila 2024

Anna Trubetskaya, Huy Quang L锚, Jenni Leppiniemi, Tetyana Koso, Teemu V盲lisalmi, Markus B. Linder, Italo Pisano, Jinze Dou, J. J. Leahy, Eero Kontturi 2024 Algal Research

Jinze Dou, Martin K枚gler, Kavindra Kumar Kesari, Leena Pitk盲nen, Tapani Vuorinen 2023 Green Chemistry

Jinze Dou, Jincheng Wang, Sami Hietala, Dmitry V. Evtuguin, Tapani Vuorinen, Jian Zhao 2023 Green Chemistry

Jinze Dou, Evgen Multia, Xinyue Dong, Lei Wang, Tapani Vuorinen 2023 Chemical Engineering Journal

Jinze Dou, Polina Ilina, Cristina D. Cruz, Denise Nurmi, Paula Zegarra Vidarte, Marja Rissanen, P盲ivi Tammela, Tapani Vuorinen 2023 Journal of Agricultural and Food Chemistry

Jinze Dou, Toni Varila, Juha-Pekka Salminen, Sari Tuomikoski, Sami Hietala, Maria Hemmi, Tao Hu, Ulla Lassi, Tapani Vuorinen 2023 Separation and Purification Technology

Rafael Grande, Riikka R盲is盲nen, Jinze Dou, Satu Rajala, Kiia Malinen, Paula A. Nousiainen, Monika 脰sterberg 2023 ACS Omega

Yingjie Guo, Zheng Zhang, Jinze Dou, Guodong Liu, Xuezhi Li, Jian Zhao 2023 Carbohydrate Polymers
More information on our research in the Aalto research portal.
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In September, 15 new Academy Researcher Fellows will start at Aalto

The Academy of Finland has granted Aalto University funding for 15 Academy Research Fellowships

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