Arja Miettinen-Oinonen

VTT Technical Research Centre of Finland, Esbo, Southern Finland Province, Finland

Are you Arja Miettinen-Oinonen?

Claim your profile

Publications (11)18.36 Total impact

  • Arja Miettinen-Oinonen, Marja Paloheimo, Raija Lantto, Pirkko Suominen
    [Show abstract] [Hide abstract]
    ABSTRACT: In the search for suitable cellulase combinations for industrial biofinishing of cotton, five different types of Trichoderma reesei strains were constructed for elevated cellobiohydrolase production: CBHI overproducers with and without endoglucanase I (EGI), CBHII overproducers with and without endoglucanase II (EGII) and strains overproducing both CBHI and CBHII without the major endoglucanases I and II. One additional copy of cbh1 gene increased production of CBHI protein 1.3-fold, and two copies 1.5-fold according to ELISA (enzyme-linked immunosorbent assay). The level of total secreted proteins was increased in CBHI transformants as compared to the host strain. One copy of the cbh2 expression cassette in which the cbh2 was expressed from the cbh1 promoter increased production of CBHII protein three- to four-fold when compared to the host strain. T. reesei strains producing elevated amounts of both CBHI and CBHII without EGI and EGII were constructed by replacing the egl1 locus with the coding region of the cbh1 gene and the egl2 locus with the coding region of cbh2. The cbh1 was expressed from its own promoter and the cbh2 gene using either the cbh1 or cbh2 promoter. Production of CBHI by the CBH-transformants was increased up to 1.6-fold and production of CBHII up to 3.4-fold as compared with the host strain. Approximately similar amounts of CBHII protein were produced by using cbh1 or cbh2 promoters. When the enzyme preparation with elevated CBHII content was used in biofinishing of cotton, better depilling and visual appearance were achieved than with the wild type preparation; however, the improvement was not as pronounced as with preparations with elevated levels of endoglucanases (EG).
    Journal of Biotechnology 04/2005; 116(3):305-17. · 3.18 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: The capabilities of tyrosinase and peroxidase to activate tyrosine residues of wool fibres and to catalyze crosslink formation between peptides derived from a wool protein hydrolyzate were investigated. Peroxidases were able to catalyse oxidation of wool fibres corresponding to 35–40% of the tyrosine residues located on the wool surface or 2% of the tyrosine residues in the wool fibre. Similar fibre surface modification was detected with tyrosinase and a fungal peroxidase using x-ray photoelectron spectroscopy. Tyrosinase did not show detectable activation of fibres measured as oxygen consumption. Tyrosinase was, however, able to crosslink peptides of 3–10 kDa derived from enzymatically hydrolysed wool fibres. Surprisingly, no crosslinking was detected with peroxidase.
    Journal of the Textile Institute 03/2005; 96(2):109-116. · 0.73 Impact Factor
  • Source
    Enzyme and Microbial Technology 05/2004; 34(6):624. · 2.59 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Culture supernatants from strains of Melanocarpus albomyces, Myceliophthora thermophila, Chaetomium thermophilum, and Sporotrichum thermophilum were tested for their ability to release dye in neutral pH conditions from indigo-dyed cotton-containing fabric in biostoning applications. The supernatants from M. albomyces worked well in biostoning, with low backstaining. Three cellulases were purified to homogeneity from the culture medium of this species. Two of the cellulases were endoglucanases with apparent molecular masses of 20 and 50 kDa. The 20 kDa endoglucanase was a relatively heat-stable cellulase with high pH optimum. The partially purified enzyme crystallized spontaneously at pH 4.0 and 7 °C. The 50 kDa endoglucanase also had activity against 4-methylumbelliferyl-β-d-lactoside (MUL) and was active over a wide range of pH values. The third purified cellulase was the 50 kDa cellobiohydrolase with low MUL activity at acidic pH and detectable activity towards filter paper and acid swollen Solca Floc-cellulose, but no endoglucanase activity. The purified 20 kDa endoglucanase performed well in biostoning of denim fabric at neutral pH. Addition of the purified 50 kDa endoglucanase or the 50 kDa cellobiohydrolase to the 20 kDa endoglucanase decreased backstaining in biostoning.
    Enzyme and Microbial Technology. 01/2004;
  • [Show abstract] [Hide abstract]
    ABSTRACT: In our previous study, three purified cellulases of Melanocarpus albomyces proved to be effective in biostoning application at neutral pH [Enzyme Microb. Technol., accepted for publication]. We cloned and sequenced three genes of M. albomyces, which encode a 20 kDa and two 50-kDa polypeptides. The 20-kDa protein (Cel45A) and one of the 50-kDa proteins (Cel7A) are endoglucanases of the glycosyl hydrolase families 45 and 7, respectively. The other 50-kDa protein (Cel7B) is a family 7 cellobiohydrolase. None of the cellulases harbors a cellulose binding domain (CBD). These genes were expressed in Trichoderma reesei under the control of the T. reesei cbh1 promoter and the proteins detected in the culture medium. The endoglucanase production levels of the cel45A- and cel7A-transformants were several times higher than those of the parental M. albomyces strain. The sizes of Cel45A, Cel7A and Cel7B proteins produced by the transformants were the same as the sizes of the corresponding proteins purified from M. albomyces. Cellulase preparations produced by the cel45A transformants performed well at neutral pH in stone-washing of denim fabric and caused considerably less backstaining as compared to the acid cellulase product of T. reesei.
    Enzyme and Microbial Technology. 01/2004;
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: The mode of action of monocomponent purified Trichoderma reesei cellobiohydrolases (CBHI and CBHII) and endoglucanases (EGI and EGII) on cotton fabrics was studied by analyzing the weight loss of the fabric, the reducing sugars, the soluble oligosaccharides and the molecular weight of the cotton powder formed. The impact of mechanical action on these factors was also evaluated. EGI and EGII released the highest amounts of reducing sugars and soluble oligosaccharides in both treatments with or without additional mechanical action. After cellulase treatment without additional mechanical action, all of the cellulases were found to have reduced the molecular weight of cotton poplin powder. When mechanical action was combined with enzyme treatments, only EGII reduced the molecular weight. The weight loss of EG-treated fabrics was clearly higher than the weight loss of CBH-treated fabrics with both low and high mechanical action levels. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 1917–1922, 2003
    Journal of Applied Polymer Science 11/2003; 90(7):1917 - 1922. · 1.40 Impact Factor
  • Source
    Arja Miettinen-Oinonen, Pirkko Suominen
    [Show abstract] [Hide abstract]
    ABSTRACT: Trichoderma reesei strains were constructed for production of elevated amounts of endoglucanase II (EGII) with or without cellobiohydrolase I (CBHI). The endoglucanase activity produced by the EGII transformants correlated with the copy number of the egl2 expression cassette. One copy of the egl2 expression cassette in which the egl2 was under the cbh1 promoter increased production of endoglucanase activity 2.3-fold, and two copies increased production about 3-fold above that of the parent strain. When the enzyme with elevated EGII content was used, an improved stonewashing effect on denim fabric was achieved. A T. reesei strain producing high amounts of EGI and -II activities without CBHI and -II was constructed by replacing the cbh2 locus with the coding region of the egl2 gene in the EGI-overproducing CBHI-negative strain. Production of endoglucanase activity by the EG-transformant strain was increased fourfold above that of the host strain. The filter paper-degrading activity of the endoglucanase-overproducing strain was lowered to below detection, presumably because of the lack of cellobiohydrolases.
    Applied and Environmental Microbiology 09/2002; 68(8):3956-64. · 3.95 Impact Factor
  • L. Heikinheimo, J. Buchert, A. Miettinen-Oinonen, P. Suominen
    [Show abstract] [Hide abstract]
    ABSTRACT: Cellulases are widely used to age denim fabrics. In this work the effects of three purified monocomponent cellulases, EG I, EG II, and CBH I, and two different cellulase mixtures produced by genetically modified strains of Trichoderma reesei are compared for stone washing denim fabrics. Stone washing effects are evaluated by analyzing the soluble reducing sugars, absorbance, and lightness values of the treatment solutions. The prop erties of denim swatches are evaluated by reflectance units and by a panel. Purified cellulase EG II is most effective at removing color from denim, producing a good stone washing effect with the lowest hydrolysis level. Treatment with CBH I does not produce any stone washing effect, even at high enzyme dosages. The commercial cellulase Ecostone® L produces a good stone washing effect, but the experimental cellulase mixture Cellulase B removes color only with the highest enzyme dosage, i.e., when the amount of EGS in the mixture is high enough.
    Textile Research Journal 01/2000; 70(11):969-973. · 1.14 Impact Factor
  • A Miettinen-Oinonen, T Torkkeli, M Paloheimo, H Nevalainen
    [Show abstract] [Hide abstract]
    ABSTRACT: An Aspergillus gene coding for a pH 2.5 acid phosphatase enzyme was successfully overexpressed in Trichoderma reesei under the strong main cellobiohydrolase I (cbh 1) promoter. The best transformants produced up to 240 times more of the acid phosphatase than the Aspergillus strain from which the phosphatase gene was originally isolated. The recombinant enzyme was effectively secreted into the culture medium both by its own and the cbh 1 secretion signal. The heterologous pH 2.5 acid phosphatase enzyme produced by the Trichoderma transformants was seen as four protein bands of about 55-66 kD resulting from variable glycosylation in Trichoderma. The activity of the recombinant enzyme was not affected. Enzyme preparations rich in both cellulose and phytate hydrolysing enzymes are of interest in the animal feed industry.
    Journal of Biotechnology 11/1997; 58(1):13-20. · 3.18 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: The genes encoding phytase (EC 3.1.3.8) and pH 2.5-optimum acid phosphatase (EC 3.1.3.2) have been cloned and sequenced from Aspergillus niger var. awamori. The translated nucleotide sequences yielded polypeptides of 467 and 479 amino acids (aa) for phytase and acid phosphatase, respectively. The genes were isolated using oligodeoxyribonucleotide probes based on the aa sequences of the purified proteins. Recombinant A. niger var. awamori strains carrying additional copies of the gene sequences demonstrated elevated enzyme activities.
    Gene 11/1993; 133(1):55-62. · 2.20 Impact Factor
  • Source
    Arja Miettinen-Oinonen