Browsing by Author "Linder, Markus"

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  • Adhesive properties of the silk-mussel protein
    (2022-06-13) Purho, Timo
     Kemian tekniikan korkeakoulu | Master's thesis
    There is a rising interest in the use of new adhesive materials in the field of tissue engineering, especially in working in wet environments. Silk protein is one of the natural polymers showing great potential in future applications of tissue engineering as a bioadhesive with high biocompatibility, great mechanical properties, and chemical and physical modifiability. The challenge is that most synthetic adhesives won’t work properly in wet environments. Wet-resistant adhesion proteins from marine mussels have the ability to form adhesive solid interactions with many different types of substrates in wet conditions. A key element for good adhesive properties has been suggested to be the high content of 3,4-dihydroxyphenyl-L-alanine (DOPA). Combining mechanical properties from silk protein with the wet adhesion of mussel foot protein could create great bioadhesives for medical applications. The aim of this thesis was to investigate the adhesive properties of the silk-like fusion protein with the aid of mussel foot protein and DOPA modification. The hypothesis was that mussel foot protein and DOPA modification enhance the adhesive properties of the silk protein. Escherichia coli (E.coli) was used to produce protein constructs SC2-ADF3-SC2, SMT3-mfp1-ST, and SMT3-mfp1-ST-DOPA. Adhesive properties were then tested on acrylic (poly(methyl methacrylate)), aluminum, and glass slides, and adhesive strength was tested with lap shear tests. The results were promising showing a higher increase in adhesive strength with samples including DOPA. The results followed the hypothesis but the limited amount of successful tests prevents full acceptance of the hypothesis. Consequently, further conclusions must be drawn with this in mind.
  • An AMA plasmid-based CRISPR-Cas9 genome editing tool for a non-model filamentous fungus
    (2024-05-20) Nieminen, Katri
     Kemian tekniikan korkeakoulu | Master's thesis
    This thesis aimed to develop a CRISPR-Cas9 genome editing tool for the non-model fila-mentous fungus Paecilomyces variotii employing the AMA plasmid since a lack of selection markers and low frequency of gene targeting is a common problem in filamentous fungi genome editing. AMA1 is the origin of replication and has been effectively employed in many filamentous fungi, including Aspergillus species. Since the AMA plasmid is rarely integrated into the genome and is easily removed after transformation, it may provide a solution especially related to these challenges. The efficiency of the constructed AMA plasmid-based approach was tested for gene deletion, gene insertion, and editing of several genes simultaneously. Two different strategies were chosen to implement AMA-based gRNA expression which were ribozymes flanked sgRNA transcript synthesized by Pol II promoter and sgRNA transcript driven by Pol III U6 promoter. As a result, the U6 promoter-based AMA plasmid approach was proven to be capable of gene deletions and achieved a 53% efficiency rate in gene insertion. The Ribozyme-based approach yielded weaker efficiency, although it was proved to be functional for both gene deletion and insertion. The simultaneous editing of multiple genes could not be achieved and requires further development and optimization.
  • Amyloider som olika nanomaterial inom medicin, vävnadsteknik och elektronik
    (2015-04-27) Olkkonen, Linda
     Kemiantekniikan korkeakoulu | Bachelor's thesis
  • Binding of cellobiohydrolases I and II of Trichoderma reesei to cellulose; use of tritium labeling
    (1998) Palonen, Hetti
     Helsinki University of Technology | Master's thesis
    Työssä selvitettiin Trichoderma reesein sellobiohydrolaasi I:n ja II:n sekä niiden yksittäisten osien, katalyyttisen osan ja selluloosaan sitoutuvan osan (CBD) sitoutumista kiteiseen bakteeriselluloosaan. Proteiinit leimattiin in vitro [3]H:lla. Radioaktiivisen leiman avulla pystyttiin mittaamaan tarkasti alhaisia proteiinin konsentraatiota nestefaasissa. Leimaus suoritettiin pelkistävällä metylaatiolla, jolloin tritiumatomeja sisältävät metyyliryhmät kiinnittyivät proteiinin vapaisiin aminoryhmiin. Leimatut preparaatit puhdistettiin geelisuodatuksella ja puhtaus tarkistettiin ioninvaihtokromatografialla. Metyloitujen entsyymien katalyyttinen aktiivisuus ja sitoutumiskyky säilyivät muuttumattomina. Sitoutuminen oli lämpötilasta riippuvaista. Määritetyistä sitoutumisisotermeistä ilmeni, että alhaisissa lämpötiloissa proteiinit sitoutuivat selvästi paremmin selluloosaan. Lisäksi todettiin, että kokonaiset entsyymit sitoutuivat paremmin kuin niiden osat. Katalyyttiset osat sitoutuivat heikoimmin. CBH I:n sitoutuminen oli reversiibeliä ja se voitiin irrottaa bakteeriselluloosasta puskurinlisäyksellä. Laimennoksen jälkeen eri ajanhetkinä tehdyt mittaukset osoittivat, että uusi tasapainotila muodostui samalle isotermille. CBH II:n sitoutuminen oli osittain reversiibeliä. Sellobioosi lisäsi molempien entsyymien katalyyttisten osien sitoutumista, mutta kokonaisen CBH II:n adsorptio väheni. Selluloosan hydrolyysin edetessä entsyymien sitoutuminen jäljellä olevaa substraattia kohtaan muuttui yllättävästi. Hydrolyysin alkuvaiheessa sitoutuminen noudatti sitoutumisisotermin tasapainoa, mutta kun noin puolet näytteen selluloosasta oli hajonnut, sitoutuneen entsyymin määrä jäljellä olevaa selluloosaa kohti kasvoi 2 - 3 -kertaiseksi. Työn kirjallisuusosassa käsiteltiin proteiinien kemiallista leimausta in vitro. Proteiinien muokattavissa olevat aminohappojen sivuketjut sekä niihin kohdistuvat tärkeimmät kemialliset reaktiot esiteltiin. Tärkeimpiä leimaustekniikoita eli fluoresenssileimoja, proteiinien biotinylaatiota ja radioisotooppileimausta tarkasteltiin laajemmin.
  • Biojätteen käsittelyn kannattavuus pienessä biokaasulaitoksessa
    (2016-06-14) Saarela, Lauri
     Kemian tekniikan korkeakoulu | Master's thesis
    Diplomityössä tutkitaan mahdollisen kauppakeskuskiinteistön yhteydessä olevan biojätettä käsittelevän biokaasulaitoksen kannattavuutta. Laitoksen kannattavuus perustuu siihen, että sen avulla käsitellään kaikki kauppakeskuksessa syntyvät biojätteet, jolloin näistä ei tarvitse maksaa tyypillistä kuljetus- tai käsittelymaksua. Kannattavuustutkimusta varten laitos suunniteltiin lähtökohtaisesti yksinkertaiseksi ja edulliseksi. Laitoksen biojätteen käsittelyn kapasiteetiksi valittiin 25 t/kk. Suunnitellussa laitoksessa käytetään DRANCO-prosessin hitaasti sekoittavaa mädätysreaktoria. Siinä syntynyttä biokaasua ei jatkojalosteta, vaan se poltetaan raakana kaasukattilassa lämmöksi. Syntyvällä lämpimällä vedellä lämmitetään biokaasulaitosta ja kauppakeskuskiinteistöä. Biokaasulaitoksen mädätysjäännös kuljetetaan paikallisille viljelijöille peltolevitystä varten ilmaiseksi. Kannattavuustutkimuksessa saatiin biokaasulaitokselle kymmenen vuoden ajalta efektiiviseksi koroksi 9,44 %. Herkkyysanalyysi paljasti, että biokaasulaitos on herkin laitoksen investointikustannusten ja biojätemaksujen prosentuaaliselle muutokselle. Kahden muuttujan herkkyysanalyysissä näiden kahden muuttujan välillä nähtiin, että on olemassa useita realistisia vaihtoehtoja, joilla biokaasulaitoksen sisäinen korko on yli 10 %. Tätä arvoa pidettiin tutkimuksessa kannattavuuden perusvaatimuksena.
  • Biosynthesis of tetrahydroisoquinolines and their intermediates with Bacillus subtilis
    (2022-12-13) Heikkinen, Jenni
     Kemian tekniikan korkeakoulu | Master's thesis
    The objective of this Master’s thesis was to produce tetrahydroisoquinolines and their derivatives from bulk and inexpensive starting materials by utilizing a chemoenzymatic route. The aim of the work was to design and produce individually inducible expression system for acetolactate synthase, ω-transaminase, (R)-salsolinol synthase, (S)-norcoclaurine synthase and phenylethanoyl-N-methyltransferase (PNMT) in Bacillus subtilis. In addition, the aim of this work was to model the tertiary structure of the enzymes and proteins used in the work using in-silico methods for future use. A purchase order was placed for the designed de-novo plasmid which the custom gene synthesis company failed to produce. However, a partially constructed plasmid was acquired which was able to replicate in the host and contained intact sequences for the expression of (S)-norcoclaurine synthase and PNMT under eukaryotic promoters. The enzyme production for these enzymes were analyzed with SDS-PAGE. The results indicated successful enzyme expression for (S)-norcoclaurine synthase under Cu2+ inducible eukaryotic promoter, but the expression of PNMT under eukaryotic Fe3+ promoter was inconclusive. The expression system was re-designed and purchased which yielded a generic cloning shuttle vector for Escherichia coli and B. subtilis, capable to integrate desired payload into B. subtilis’ alpha-amylase (AmyE) locus. Genes for expression operons, the first consisting of ω-transaminase and the second consisting (R)-salsolinol synthase and (S)-norcoclaurine synthase were purchased and eventually received and cloned successfully into the shuttle vector successfully after modification of the defective promoter driving the fluorescent protein reporter producing gene. Gene synthesis companies were not able to produce operon for acetolactate synthase. Also the expression of PNMT was omitted to keep the project in reference time. Electroporation and thus other planned expression experiments for these two plasmids in B. subtilis could not be performed due the availability problems of laboratory space. Realistic tertiary structure models of the enzymes and proteins used in the work were successfully created, which can be used in future work.
  • Characterising the effect of green fluorescent protein fusion on recombinant spider silk fibres
    (2024-08-29) Ahlberg, Martin
     Kemian tekniikan korkeakoulu | Master's thesis
    Renewable biomimetic and bio-based materials are gathering increased interest as sustainable replacements for fossil man-made materials. Spider silk is a natural protein-based fibre that outperforms synthetic fibres, making it attractive for many applications. Industrial production of spider silk requires the use of recombinant protein technology, and functionalizing recombinant silk relies on the design of artificial silk proteins that form fibres on par with native silk. This requires knowledge about mechanisms underlying fibre assembly and how sequence structure relates to assembly and performance. Fluorescent marker proteins are sometimes used in such efforts, but the spinnability and mechanical properties of fusions are seldom tested. Moreover, developing silk with unique properties, like built-in colour at the molecular level, without hampering performance, would further boost its value. Three previously developed recombinant spider silk constructs were fused with the commonly used marker protein enhanced green fluorescent protein (eGFP). The three eGFP silk constructs were produced alongside their corresponding non-eGFP constructs either in shake flasks or in a bioreactor to assess the possibility of scale- up. Constructs were biomimetically spun into fibres with a wet spinning approach that only uses aqueous solutions, and fibres were tensile tested to compare the mechanical properties and behaviour of eGFP silk to non-eGFP silk. Spinning parameters were toggled to assess how eGFP silk behaves in different conditions and to evaluate if its performance could be improved by minor protocol alterations. The specific impact of eGFP on fibre structure and performance was evaluated. The eGFP silk variants were spinnable just as their corresponding non-eGFP variants and spinning yielded visibly green eGFP fibres. Mechanical testing revealed that eGFP silk behaves differently than non-eGFP silk and has inferior mechanical properties. Tweaking spinning conditions resulted in stronger eGFP fibres, but they were still weaker than non-eGFP ones. Reasons for differences could be dissimilar parameters used in spinning, which makes results demanding to compare, but also divergence in secondary structure, unfavourable intermolecular interactions, and steric hindrance, resulting from eGFP fusion.
  • Chitin-binding Proteins in Novel Material Design
    (2020-05-02) Majaniemi, Jouni
     Kemiantekniikan korkeakoulu | Bachelor's thesis
  • Chromatographic fractionation of virus inactivated blood plasma
    (1993) Linder, Markus
     Helsinki University of Technology | Master's thesis
  • Cleavage of recombinant proteins at poly-His sequences by Co(II) and Cu(II)
    (2007-08) Anberg, Martina; Jäntti, Jussi; Heilimo, Saara; Pihkala, Päivi; Paananen, Arja; Koskinen, Ari M.P.; Söderlund, Hans; Linder, Markus
     A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
    Improved ways to cleave peptide chains at engineered sites easily and specifically would form useful tools for biochemical research. Uses of such methods include the activation or inactivation of enzymes or the removal of tags for enhancement of recombinant protein expression or tags used for purification of recombinant proteins. In this work we show by gel electrophoresis and mass spectroscopy that salts of Co(II) and Cu(II) can be used to cleave fusion proteins specifically at sites where sequences of His residues have been introduced by protein engineering. The His residues could be either consecutive or spaced with other amino acids in between. The cleavage reaction required the presence of low concentrations of ascorbate and in the case of Cu(II) also hydrogen peroxide. The amount of metal ions required for cleavage was very low; in the case of Cu(II) only one to two molar equivalents of Cu(II) to protein was required. In the case of Co(II), 10 molar equivalents gave optimal cleavage. The reaction occurred within minutes, at a wide pH range, and efficiently at temperatures ranging from 0°C to 70°C. The work described here can also have implications for understanding protein stability in vitro and in vivo.
  • Controlled biocide release from hierarchically-structured biogenic silica: surface chemistry to tune release rate and responsiveness
    (2018-12-01) Mattos, Bruno D.; Tardy, Blaise L.; Mohammadi, Pezhman; Kämäräinen, Tero; Linder, Markus; Schreiner, Wido H.; Magalhães, Washington L.E.; Rojas, Orlando J.
     A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
    Biocides are essential for crop protection, packaging and several other biosystem applications. Therein, properties such as tailored and controlled release are paramount in the development of sustainable biocide delivery systems. We explore the self-similar nano-organized architecture of biogenic silica particles to achieve high biocide payload. The high surface area accessibility of the carrier allowed us to develop an efficient, low energy loading strategy, reaching significant dynamic loadings of up to 100 mg·g-1. The release rate and responsiveness were tuned by manipulating the interfaces, using either the native hydroxyl surfaces of the carrier or systems modified with amines or carboxylic acids in high density. We thoroughly evaluated the impact of the carrier-biocide interactions on the release rate as a function of pH, ionic strength and temperature. The amine and carboxyl functionalization strategy led to three-fold decrease in the release rate, while higher responsiveness against important agro-industrial variables. Key to our discoveries, nanostructuring thymol in the biogenic silica endowed systems with controlled, responsive release promoting remarkable, high and localized biocidal activity. The interfacial factors affecting related delivery were elucidated for an increased and localized biocidal activity, bringing a new light for the development of controlled release systems from porous materials.
  • Controlled communication between physically separated bacterial populations in a microfluidic device
    (2018) Osmekhina, Ekaterina; Jonkergouw, Christopher; Schmidt, Georg; Jahangiri, Farzin; Jokinen, Ville; Franssila, Sami; Linder, Markus
     A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
    The engineering of microbial systems increasingly strives to achieve a co-existence and co-functioning of different populations. By creating interactions, one can utilize combinations of cells where each population has a specialized function, such as regulation or sharing of metabolic burden. Here we describe a microfluidic system that enables long-term and independent growth of fixed and distinctly separate microbial populations, while allowing communication through a thin nano-cellulose filter. Using quorum-sensing signaling, we can couple the populations and show that this leads to a rapid and stable connection over long periods of time. We continue to show that this control over communication can be utilized to drive nonlinear responses. The coupling of separate populations, standardized interaction, and context-independent function lay the foundation for the construction of increasingly complex community-wide dynamic genetic regulatory mechanisms.
  • Demineralisoidun heratiivisteen valmistusmahdollisuudet panostoimista elektrodialyysiä hyödyntäen
    (2020-08-18) Hintsala, Elise
     Kemian tekniikan korkeakoulu | Master's thesis
    Juustonvalmistuksessa syntyvä hera sisältää paljon tärkeitä proteiineja ja vitamiineja. Jotta näitä arvokkaita ainesosia pystyttäisiin hyödyntämään elintarvikkeissa kuten lastenruuissa, on heran mineraalipitoisuutta vähennettävä. Mineraalipitoisuus pystytään vähentämään käyttämällä eri demineralisointi- eli suolanpoistotekniikoita kuten elektrodialyysiä (ED), ioninvaihtoa (IX) ja nanosuodatusta (NF). Tämän työn tavoitteena oli selvittää uuden tyyppisen ED-tekniikan soveltuvuutta valmistaa energiatehokkaasti heratiivistettä, jonka kuiva-aineen tuhkapitoisuus on alle 1% (Demi® 90). Suolanpoiston tehokkuuden, energiankulutuksen ja saannon kannalta parhaimmat prosessin parametrit kuten lämpötila, jännite ja syötön kuiva-ainepitoisuus määritettiin. Toinen tavoite oli selvittää ED-tekniikan suolanpoistotehokkuus poistettaessa heran mineraaleista 50% (kuiva-aineen tuhkapitoisuus alle 4%) ja 70% (kuiva-aineen tuhkapitoisuus alle 3%). Tällä tavalla pystytiin vertaamaan uuden tyyppistä ED-tekniikkaa nykyisin käytettyyn ED-tekniikkaan. Kolmas tavoite oli, selvittää pystytäänkö nykyistä ED-prosessia tehostamaan uudella ED-tekniikalla. Nykyisellä ED-tekniikalla poistettaisiin 50% ja 70% mineraaleista ja suolanpoistoa jatkettaisiin uudentyyppisellä ED-tekniikalla. Tällöin päästäisiin alle 1% tuhkapitoisuuksiin. Tulosten mukaan tutkittu ED -tekniikka soveltui hyvin D90-tiivisteen valmistukseen suoraan nano- tai heratiivisteestä. Suolanpoiston tehokkuuden kannalta optimiparametreiksi valittiin 12V, 25°C sekä 20%:n syötön kuiva-ainepitoisuus. ED-tekniikan avulla pystyttiin myös valmistamaan D70-tiivisteettä samalla kapasiteetilla kuin nykyinen prosessi, mutta heikommalla proteiini- ja kuiva-ainesaannoilla. Tämän lisäksi D90-tiivisteen valmistus onnistui korkealla kapasiteetilla ja hyvällä saannolla, kun syötteenä käytettiin D50- tai D70-tiivisteitä.
  • Developing an intracellular screening method for recombinant spider silk proteins
    (2023-08-21) Sammalisto, Fred-Eric
     Kemian tekniikan korkeakoulu | Master's thesis
    Bio-based materials are becoming increasingly important in our society to ensure a sustainable technological evolution. Nature has evolved a multitude of functional materials to fit different purposes. Spider silk is a natural protein-based fiber material outperforming any synthetic fossil-based fiber and has many attractive applications. Industrial use of spider silk, however, relies on recombinant protein technology, and to optimize the properties of the material requires knowledge about the natural molecular assembly and underlying mechanisms therein, such as liquid-liquid phase separation. To enable efficient de novo protein engineering, fast and high throughput screening methods for protein libraries consisting of many variants are essential. A library of rationally mutated variants of a previously characterized recombinant spider silk construct was used to investigate whether a previously developed screening method relying on probing intracellular spider silk coacervates using fluorescence and microscopy -based analytical techniques could be used to screen for spider silk variants with enhanced properties. The variants were assessed based on protein expression level, solubility and phase behaviour. The method was validated by comparing results obtained in this thesis with previously reported data. Then, a novel library of naturally occurring spider silk sequences was created to be screened with the method. Finally, to what degree the phase behaviour and viscosity of the silk protein affects fiber formation and mechanical performance was investigated. For this, selected variants were biomimetically spun into silk fibers using an approach that mimics the natural spinning process in spiders, and the spun fibers were mechanically tested. The screening method could successfully be applied on different libraries of spider silk proteins. Soluble variants could be identified in most cases by observing the appearance of intracellular coacervates with relatively high correlation with results from SDS-PAGE and FRAP analysis. Variants forming solid-like coacervates cannot be spun into fibers, however, no obvious correlation between the degree of coacervate liquid-likeness and spinnability or mechanical performance was found due to the limited amount of spinning data.
  • Development of analysis method for quality control of bioink printing
    (2021-08-23) Hertzberg, Jasmin
     Kemian tekniikan korkeakoulu | Master's thesis
  • Development of surface binding peptides using phage display
    (2012) Haka, Jaana
     School of Chemical Engineering | Master's thesis
    Finding tools for optimizing the performance of biomedical materials is under continuous research. In this thesis, a unique strategy for surface functionalization using material-specific peptides generated via phage display is presented. Phage display is a powerful selection method that enables screening of a large library of randomly generated peptides in favour of peptide sequences with the highest binding affinity to a particular surface via process called biopanning. These peptides could be utilized as binding agents or linkers in the construction of novel nanobiomaterials and control the organization, self-assembly and specific functions of the biomaterial. Besides synthetic peptides, the utilization of natural adhesive proteins, such as hydrophobins and mussel adhesive proteins are discussed in order to discover novel strategies for surface engineering of biomedical material applications. The aim is to find peptides suitable for surface functionalization of a fungal adhesive protein, hydrophobin, which has been successfully researched as a coating material for various biomedical applications. A bacteriophage library was used to screen 109 different 12-mer peptides against hydrophobin protein layer. The binding affinity and specificity of the selected phage display derived peptides were assessed using titer count analysis, enzyme-linked immunosorbent assay and quartz crystal microbalance with dissipation monitoring. The biopanning resulted in hydrophilic peptides that show binding on hydrophobin protein layer. However, no consensus sequence was observed and some of the peptide sequences seemed to be target unrelated peptides. There were significant differences in binding affinity between the phage variants, and the best variants were HFBbp2-l3 and HFBbp2-l6. Surprisingly, the binding of the phages was not selective to hydrophobin protein only but binding was observed to plastics as well. The binding properties were verified using isolated synthetic peptides of the best phage variants.
  • DNA-directed antigen array for high throughput immunosignature analysis
    (2022-05-17) Barannik, Emilia
     Kemian tekniikan korkeakoulu | Master's thesis
  • Effects of aqueous ozone on quality of fresh-cut vegetables
    (2023-03-21) Granqvist, Alexandra
     Kemian tekniikan korkeakoulu | Master's thesis
  • Elastic and pH-Responsive Hybrid Interfaces Created with Engineered Resilin and Nanocellulose
    (2017-06) Fang, Wenwen; Paananen, Arja; Vitikainen, Marika; Koskela, Salla; Westerholm-Parvinen, Ann; Joensuu, Jussi J.; Landowski, Christopher P.; Penttilä, Merja; Linder, Markus; Laaksonen, Päivi
     A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
    We investigated how a genetically engineered resilin fusion protein modifies cellulose surfaces. We characterized the pH-responsive behavior of a resilin-like polypeptide (RLP) having terminal cellulose binding modules (CBM) and showed its binding to cellulose nanofibrils (CNF). Characterization of the resilin fusion protein at different pHs revealed substantial conformational changes of the protein, which were observed as swelling and contraction of the protein layer bound to the nanocellulose surface. In addition, we showed that employment of the modified resilin in cellulose hydrogel and nanopaper increased their modulus of stiffness through a cross-linking effect.
  • Engineering flax-protein composites
    (2020-05-18) Malkamäki, Maaria
     Kemian tekniikan korkeakoulu | Master's thesis
    Nature offers endless ideas and possibilities for the design of new materials. For instance, flax fibres are natural plant fibres with high tensile strength and stiffness, and spider dragline silk has excellent mechanical strength for its weight combined with high elasticity. By coacervate-mediated (liquid-liquid phase separation) infiltration of plant cells (flax) with recombinantly produced silk-like protein, the properties of flax fibres and spider silk could be combined to create new composite materials. Understanding the mechanism by which proteins enter the plant cell wall also contributes to developing new processes to modify lignocellulosic fibres more generally. Accordingly, the aims of this thesis were to develop a method for making a composite material from flax fibres and recombinant silk-like protein, study the mechanical properties and the structure of the material, and determine whether the protein has penetrated the cell wall of flax fibres. Silk-like protein construct CBM-AQ12-CBM was modified by adding a affinity-tag StrepII in N-terminus of the protein. The silk-like proteins middle region, AQ12, is similar to spider Araneus diadematus dragline silk gene ADF3, while the terminal regions are cellulose binding domains (CBM) from Clostridium thermocellum cellulosome. The silk-like protein was expressed in Escherichia coli, the protein was combined with flax fibres, the materials mechanical properties were evaluated by tensile test and the structure of the material was studied by electron microscope. While the StrepII-tag improved the protein yield it was not found to change the properties of the protein. Results of the mechanical tests displayed significant scatter, explained in part by the range of flax fibre diameters tested. Overall, the protein treatment increased the diameter of the technical flax fibres by gluing the individual in solution into a plied structure. While the protein treated fibres were not stronger, their energy storing capacity was greater, a more uniform behaviour under stress, and differences in the type of failure were observed. The localization of the protein within the fibre and microstructure of the material remain unclear. In future, the role of fibre diameter in the response of the material to stress must be studied and the methods for imaging of the structure improved.