Browsing by Subject "xylanase"

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  • Salumäe, Astrid (Helsingin yliopisto, 2020)
    In biotechnological protein production and metabolic engineering, regulating the expression of genes is essential. For this, expression systems composed of promoters, terminators and transcription factors are essential. So far, majority of these systems use native promoters and transcription factors. That however rises two problems: 1) these systems usually work in only a set of closely related species, 2) native regulatory components can cause unintended expression levels due to the complexity of cellular regulation. Recently, a synthetic expression system (SES) was established for a wide range of fungal species. The transcription factor used in this system comprises an activation domain that originates from a virus. However, in the field of biotechnology and especially food industry, viral DNA constructs are not favorable because of customer concerns. In this paper, plant-derived activation domains were screened in Trichoderma reesei and Pichia pastoris using mCherry as a target gene for measuring the expression levels. The best expression systems were also tested for protein production in T. reesei and P. pastoris. We tested the production of two different proteins – a bacterial xylanase and a phytase. Two of the novel activation domains provided similar expression levels to the viral activation domain in both fungi. In addition, we developed optimized expression systems for an unconventional yeast from Zygosaccharomyces spp. using the novel transcription factors. The best SES version was used for secretion signal sequence screening for xylanase protein production. To further improve the use of T. reesei as a production host, the CRISPR-Cas9 system with the Cas9 D10A nickase version was tested for transformation of T. reesei. Here, we demonstrated the genomic integration and expression of Cas9 D10A nickase in T. reesei using the SES system with the novel plant-derived activation domain. Furthermore, we successfully transformed the T. reesei Cas9 D10A nickase expressing strain using only guide-RNAs and a donor DNA.
  • Rahikainen, Jenni; Anbarasan, Sasikala; Wahlström, Ronny; Parviainen, Arno; King, Alistair W. T.; Puranen, Terhi; Kruus, Kristiina; Kilpeläinen, Ilkka; Turunen, Ossi; Suurnäkki, Anna (2018)
    BACKGROUNDThis study elaborates the possibility to apply combined ionic liquid (IL) and enzyme treatments for pulp fibre modification. The approach involves swelling of fibre surfaces with IL followed by enzymatic modification of the disrupted fibre surface using carbohydrate active enzymes. RESULTSThe capacity of seven cellulose-dissolving or cellulose-swelling ionic liquids to swell pulp fibres was compared. In addition, thirteen cellulases and five xylanases were screened for their IL tolerance, which determines their applicability in combined or sequential IL-enzyme treatments of fibres. Among the studied ionic liquids, 1-ethyl-3-methylimidazolium dimethylphosphate ([EMIM]DMP) and 1,3-dimethylimidazolium dimethylphosphate ([DMIM]DMP) had the strongest effect on fibre swelling. These solvents were also found to be the least inactivating for the studied enzymes. CONCLUSIONEnzyme compatibility and cellulose-dissolving capability are not two conflicting properties of an ionic liquid. (c) 2017 Society of Chemical Industry
  • Koivunen, Erja; Talvio, Eija; Valkonen, Eija; Tupasela, Tuomo; Tuunainen, Petra; Valaja, Jarmo (2016)
    The aim was to study the effects of dietary pea inclusion and the addition of Avizyme 1200 -enzyme cocktail on broiler performance, intestinal viscosity and organoleptic quality of meat. The experimental design was a 4 x 2 factorial, the factors being dietary pea inclusion (0, 150, 300 and 450 g kg(-1)) in the diets fed from day 9 to day 38 and the addition of Avizyme 1200 enzyme cocktail including amylase, protease and xylanase during the entire experiment. The growth of birds improved (p 0.05). In conclusion, 450 g kg(-1) peas can be used in the broiler grower diets without negative effects on the bird performance. The use of enzyme cocktail improves bird performance.