| 1. |
- Christakopoulos, Paul, et al.
(författare)
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Functional characterization of a cellulose binding xylanase from Fusarium oxysporum
- 1996
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Ingår i: Biotechnology letters. - 0141-5492 .- 1573-6776. ; 18:3, s. 349-354
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Tidskriftsartikel (refereegranskat)abstract
- An extracellular endoxylanase from Fusarium oxysporum binds onto crystalline cellulose. A small peptide (~ 2kDa) could be isolated after partial proteolysis of the native protein. It consists of 18 amino acids, is located in the C-terminal region of the protein and corresponds functionally to a cellulose binding domain (CBD), the first one to be reported in a fungal xylanase. The amino acid sequence of this peptide shows no homology with any known CBD
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| 2. |
- Christakopoulos, Paul, et al.
(författare)
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Production of an esterase from Fusarium oxysporum catalysing transesterification reactions in organic solvents
- 1998
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Ingår i: Process Biochemistry. - 1359-5113 .- 1873-3298. ; 33:7, s. 729-733
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Tidskriftsartikel (refereegranskat)abstract
- The production of an esterase by Fusarium oxysporum, grown on tomato skins as the sole carbon source, was studied in submerged and solid state cultures. Under optimum growth conditions, enzyme yields as high as 7·3 U/ml of culture medium and 19·4 U/g of carbon source were obtained. The esterase catalysed the synthesis of esters in organic solvents. Geraniol was transacetylated in hexane by the esterase using triacetyl as an acetyl donor. The geranyl acetate yield was 68%.
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| 3. |
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| 4. |
- Agnantiari, G., et al.
(författare)
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A Purified α-galactosidase from aspergillus niger with enhanced kinetic characteristics
- 1991
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Ingår i: Acta Biotechnologica. - : Wiley. - 0138-4988 .- 1521-3846. ; 11:5, s. 479-484
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Tidskriftsartikel (refereegranskat)abstract
- Extracellular α-galactosidase from Aspergillus niger was purified 128-fold over the crude extract by gel filtration, ion exchange chromatography and chromatofocusing. Certain substrates and end products affected enzyme activity. Among the former p-nitrophenyl-α-galactopyranoside (PNPG) inhibited the enzyme at 1.4 mM while melibiose did not inhibit α-galactosidase at concentrations up to 50 mM. Enzymic end products such as glucose did not inhibit the enzyme at concentrations up to 100 mM while galactose exhibited a competitive inhibition with a Ki = 1.29 mM. The kinetic characteristics of the enzyme compared favourably to other microbial α-galactosidases and make it suitable for food process applications.
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| 5. |
- Caridis, K A, et al.
(författare)
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Control of catalase production and purity by altering certain nutritional factors of Alternaria alternata growth medium
- 1991
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Ingår i: Biotechnology letters. - 0141-5492 .- 1573-6776. ; 13:1, s. 35-38
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Tidskriftsartikel (refereegranskat)abstract
- Both activity level of catalase and presence of glucose oxidase as an impurity were controlled by the type and concentration of nitrogen and carbon source in the culture medium of Alternaria alternata. It was possible to produce glucose oxidase-free catalase at activity levels competing favourably with those reported for other catalase hyperproducing microorganisms.
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| 6. |
- Cheilas, T, et al.
(författare)
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Hemicellulolytic activity of Fusarium oxysporum grown on sugar beet pulp. Production of extracellular arabinanase
- 2000
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Ingår i: Process Biochemistry. - 1359-5113 .- 1873-3298. ; 35:6, s. 557-561
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Tidskriftsartikel (refereegranskat)abstract
- Fusarium oxysporum F3 exhibited hemicellulolytic enzymic activity when grown on sugar beet pulp, a by-product of the sugar industry. The growth medium was specifically optimised for enhanced production of extracellular arabinanase. The optimum medium contained sugar beet pulp (4%, w/v) and corn steep liquor (6%, v/v) as carbon and nitrogen sources, respectively. Arabinanase activity as high as 0.25 U/ml of culture was obtained, which compared favourably to those reported for other microorganisms. Optimal arabinanase activity was observed at pH 6-7 and 50 °C. Investigation of the degradation of the main components of sugar beet pulp showed that arabinose containing polysaccharides and pectin were first degraded, followed by the glucose-containing polysaccharides.
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| 7. |
- Christakopoulos, Paul, et al.
(författare)
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Antimicrobial activity of acidic xylo-oligosaccharides produced by family 10 and 11 endoxylanases
- 2003
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Ingår i: International Journal of Biological Macromolecules. - 0141-8130 .- 1879-0003. ; 31:4-5, s. 171-175
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Tidskriftsartikel (refereegranskat)abstract
- Acidic oligosaccharides were obtained from birchwood xylan by treatment with a Thermoascus aurantiacus family 10 and a Sporotrichum thermophile family 11 endoxylanases. The main difference between the products liberated by xylanases of family 10 and 11 concerned the length of the products containing 4-O-methyl-d-glucuronic acid. The xylanase from T. aurantiacus liberate from glucuronoxylan an aldotetrauronic acid as the shortest acidic fragment in contrast with the enzyme from S. thermophile, which liberated an aldopentauronic acid. Acidic xylooligosaccharides were separated from the hydrolysate by anion-exchange and size-exclusion chromatography (SEC) and the primary structure was determined by 13C NMR spectroscopy. The acidic xylo-oligosaccharides were tested against three Gram-positive and three Gram-negative aerobically grown bacteria, as well as against Helicobacterpylori. Aldopentauronic acid was proved more active against the Gram-positive bacteria and against H. pylori.
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| 8. |
- Christakopoulos, Paul, et al.
(författare)
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Controlling simultaneous production of endoglucanase and beta-glucosidase by Fusarium oxysporum in submerged culture
- 1995
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Ingår i: Biotechnology letters. - 0141-5492 .- 1573-6776. ; 17:8, s. 883-888
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Tidskriftsartikel (refereegranskat)abstract
- The simultaneous production of endoglucanase and β-glucosidase by Fusarium oxysporum was investigated in submerged culture. Consecutive optimization of growth conditions resulted in the correction of large activity differences, observed during production of enzymes, and substantially enhanced low enzyme yields. At optimum growth conditions yields as high as 1650 and 232 U per g of carbon source of endoglucanase and β-glucosidase were obtained respectively competing favourably with those reported for microorganisms grown on the same carbon source. The most important kinetic characteristics of the enzymes were the high temperature optima of endoglucanase (60°C) and β-glucosidase (65°C) and the exceptionally high thermostability of endoglucanase. The latter enzyme retained 50% of the activity at pH 5.0 after approximately 6.5 h at 70°C
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| 9. |
- Christakopoulos, Paul, et al.
(författare)
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Direct conversion of straw to ethanol by Fusarium oxysporum : Effect of cellulose crystallinity
- 1991
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Ingår i: Enzyme and microbial technology. - 0141-0229 .- 1879-0909. ; 13:3, s. 272-274
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Tidskriftsartikel (refereegranskat)abstract
- Wheat straw was successfully fermented to ethanol by Fusarium oxysporum F3 in a one-step process. Cellulose crystallinity was found to be a major factor in the bioconversion process. Ethanol yields increased linearly with decreasing crystallinity index. Approximately 80% of straw carbohydrates were converted directly to ethanol with a yield of 0.28 g ethanol/g−1 of straw when the crystallinity index was reduced to 23.6%.
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| 10. |
- Christakopoulos, Paul, et al.
(författare)
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Direct ethanol conversion of pretreated straw by Fusarium oxysporum
- 1991
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Ingår i: Bioresource Technology. - : Elsevier BV. - 0960-8524 .- 1873-2976. ; 35:3, s. 297-300
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Tidskriftsartikel (refereegranskat)abstract
- Factors affecting the direct conversion of alkali pretreated straw to ethanol by Fusarium oxysporum F3 were investigated and the alkali level used for pretreatment and the degree of delignification of straw were found to be the most important. A linear correlation between ethanol yield and both the degree of straw delignification and the alkali level was observed. At optimum delignified straw concentration (4% w/v), a maximum ethanol yield of 0·275 g ethanol g−1 of straw was obtained corresponding to 67·8% of the theoretical yield.
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