| 1. |
- Dimarogona, Maria, et al.
(författare)
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Structural and functional studies of a Fusarium oxysporum cutinase with polyethylene terephthalate modification potential
- 2015
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Ingår i: Biochimica et Biophysica Acta - General Subjects. - : Elsevier BV. - 0304-4165 .- 1872-8006. ; 1850:11, s. 2308-2317
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Tidskriftsartikel (refereegranskat)abstract
- BackgroundCutinases are serine hydrolases that degrade cutin, a polyester of fatty acids that is the main component of plant cuticle. These biocatalysts have recently attracted increased biotechnological interest due to their potential to modify and degrade polyethylene terephthalate (PET), as well as other synthetic polymers.MethodsA cutinase from the mesophilic fungus Fusarium oxysporum, named FoCut5a, was expressed either in the cytoplasm or periplasm of Escherichia coli BL21. Its X-ray structure was determined to 1.9 Å resolution using molecular replacement. The activity of the recombinant enzyme was tested on a variety of synthetic esters and polyester analogues.ResultsThe highest production of recombinant FoCut5a was achieved using periplasmic expression at 16οC. Its crystal structure is highly similar to previously determined Fusarium solani cutinase structure. However, a more detailed comparison of the surface properties and amino acid interactions revealed differences with potential impact on the biochemical properties of the two enzymes. FoCut5a showed maximum activity at 40οC and pH 8.0, while it was active on three p-nitrophenyl synthetic esters of aliphatic acids (C2, C4, C12), with the highest catalytic efficiency for the hydrolysis of the butyl ester. The recombinant cutinase was also found capable of hydrolyzing PET model substrates and synthetic polymers.ConclusionsThe first reported expression and crystal structure determination of a functional cutinase from the mesophilic fungus F. oxysporum with potential application in surface modification of PET synthetic polymers.General significanceFoCut5a could be used as a biocatalyst in industrial applications for the environmentally-friendly treatment of synthetic polymers.
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| 2. |
- Kanelli, Maria, et al.
(författare)
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Production of biodegradable polyesters via enzymatic polymerization and solid state finishing
- 2014
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Ingår i: Journal of Applied Polymer Science. - : Wiley. - 0021-8995 .- 1097-4628. ; 131:19
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Tidskriftsartikel (refereegranskat)abstract
- The synthesis of aliphatic polyesters (PEs) derived from diols (1,4-butanediol and 1,8-octanediol) and diacids or their derivatives (diethyl succinate, sebacic acid, 1,12-dodecanedioic acid, and 1,14-tetradecanedioic acid) was achieved in order to produce poly(butylene succinate) (PE 4.4), poly(octylene sebacate) (PE 8.10), poly(octylene dodecanate) (PE 8.12), and poly(octylene tetradecanate) (PE 8.14). The herein suggested procedure involved two stages, both sustainable and in accordance with the principles of "green" polymerization. The first comprised an enzymatic prepolymerization under vacuum, in the presence of diphenylether as solvent using Candida antarctica lipase B as biocatalyst, whereas a low-temperature postpolymerization step [solid state polymerization (SSP)] followed in order to upgrade the PEs quality. In the enzymatically synthesized prepolymers, the range of number-average molecular weight attained was from 3700 to 8000 g/mol with yields reaching even 97%. Subsequently, SSP of PE 4.4 and 8.12 took place under vacuum or flowing nitrogen and lasted 10-48 h, at temperatures close to the prepolymer melting point (Tm -  TSSP varied between 4°C and 14°C). The solid state finishing led to increase in the molecular weight depending on the prepolymer type, and it also contributed to improvement of the physical characteristics and the thermal properties of the enzymatically synthesized PEs
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| 3. |
- Kanelli, Maria, et al.
(författare)
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Microbial Production of Violacein and Process Optimization for Dyeing Polyamide Fabrics With Acquired Antimicrobial Properties
- 2018
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Ingår i: Frontiers in Microbiology. - : Frontiers Media S.A.. - 1664-302X. ; 9
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Tidskriftsartikel (refereegranskat)abstract
- In the present study, crude bacterial extract containing violacein is investigated for the preparation of antimicrobial polyamide fabrics. The optimal culture conditions of Janthinobacterium lividum (JL) for maximum biomass and violacein production were found to be 25°C, pH 7.0, while the addition of ampicillin of 0.2 mg mL-1 in the small scale increased violacein production 1.3-fold. In scale-up trials, the addition of 1% (v/v) glycerol in a fed-batch bioreactor, resulted in fivefold extracted crude violacein increase with final concentration of 1.828 g L-1. Polyamide 6.6 fabrics were dyed following three different processes; through simultaneous fermentation and dyeing (SFD), by incubating the fabric in the sonicated bacterial culture after fermentation and by using cell-free extract containing violacein. Maximum color change (ΔE) and color strength (K/S) obtained for SFD fabrics were 74.81 and 22.01, respectively, while no alteration of fastness and staining of dye at acid and alkaline perspiration or at water was indicated. The dyed fabrics presented significant antifungal activity against Candida albicans, C. parapsilosis, and C. krusei, as well as antibacterial properties against Escherichia coli, Staphylococcus aureus, and the S. aureus MRSA. We have shown that J. lividum cultures can be successfully used for violacein production and for simultaneous dying of fabrics resulting in dyed fabrics with antimicrobial properties without utilization of organic solvents.
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| 4. |
- Kanelli, Maria, et al.
(författare)
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Surface modification of poly(ethylene terephthalate) (PET) fibers by a cutinase from Fusarium oxysporum
- 2015
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Ingår i: Process Biochemistry. - : Elsevier BV. - 1359-5113 .- 1873-3298. ; 50:11, s. 1885-1892
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Tidskriftsartikel (refereegranskat)abstract
- Synthetic polyester fabrics occupy a great part of the textile industry production satisfying variable ordinary needs. Nonetheless, their high hydrophobicity constitutes an important weakness that impedes process manufacture, as well as permeability and evaporation of sweat when used in clothing industry. The enzymatic treatment of these materials is a modern and eco-friendly procedure that aims at the increase of the hydrophilicity through superficial modification. In this study, the enzymatic surface hydrolysis of poly(ethylene terephthalate) (PET) fabric is succeeded using a recombinant cutinase from Fusarium oxysporum. The effect of various parameters is studied for the enzymatic modification of PET, such as temperature, pH, enzyme loading and reaction time. The optimal parameters are found to be 40 °C, pH 8, and 1.92 mg enzyme loading per gram of fabric. The controlled enzymatic hydrolysis of PET textile is further confirmed and characterized using various spectroscopic and analytical methods, including Fourier Transform Infrared (FT-IR) in the Attenuated Total Reflectance mode (ATR) and X-ray photoelectron spectroscopy (XPS). Tensile test and dyeability analyses were also employed achieving a K/S increase up to 150%, confirming the successful surface modification without degrading the quality of the starting material.
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| 5. |
- Kanelli, Maria, et al.
(författare)
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Surface modification of polyamide 6.6 fibers by enzymatic hydrolysis
- 2016
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Ingår i: Process Biochemistry. - : Elsevier BV. - 1359-5113 .- 1873-3298. ; 59 A, s. 97-103
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Tidskriftsartikel (refereegranskat)abstract
- Synthetic fibers are used extensively in textile industry, however, their high hydrophobicity is a drawback that needs to be considered. The decrease of hydrophobicity can be achieved via a ‘green” root using enzymes as biocatalysts. In this study, the enzymatic surface modification of polyamide (PA) 6.6 fabric was studied with the use of the commercial protease Alcalase 2.4 L at optimal conditions. The modified fabrics were studied via dyeing parameters K/S and ΔΕ values. For treatment at 40–60 °C and pH 8 ΔE was found to be approximately 14 and K/S was 1.24-fold increased. Additionally, the enzymatic surface modification of PA textile was justified using different spectroscopy techniques, such as FTIR-ATR and XPS. FTIR-ATR indicated alterations of Cdouble bond; length as m-dashO and N-H band intensities, while via XPS, there proved to be differences in relative intensities of carbon component peaks. Finally, thermogravimetric and mechanical tests were also conducted to prove the non-degradation of the properties of the bulk material. In conclusion, the investigated enzymatic process increased the hydrophilicity with 2.7-fold increased water absorbency and 1.24-fold enhanced color strength of PA textiles, while maintaining the thermal and mechanical properties of the bulk synthetic material.
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