The feruloyl esterases FaeA1, FaeA2, FaeB1, FaeB2 from Myceliophthora thermophila C1 and MtFae1a from M. thermophila ATCC 42464 were used as biocatalysts for the transesterification of vinyl ferulate (VFA) with l-arabinose in detergentless microemulsions. The effect of parameters such as the microemulsion composition, the substrate concentration, the enzyme load, the pH, the temperature and the agitation was investigated. FaeA1 offered the highest transesterification yield (52.2 ± 4.3%) after 8 h of incubation at 50 °C using 80 mM VFA, 55 mM l-arabinose and 0.02 mg FAE mL⁻¹ in a mixture comprising of 19.8: 74.7: 5.5 v/v/v n-hexane: t-butanol: 100 mM MOPS-NaOH pH 8.0. The ability of l-arabinose ferulate (AFA) to scavenge 2,2-diphenyl-1-picrylhydrazyl (DPPH) radicals was significant (IC₅₀ 386.5 μM). AFA was not cytotoxic even at high concentrations (1 mM) however was found to be pro-oxidant at concentrations higher than 20 μM when the antioxidant activity was determined with the dichloro-dihydro-fluorescein diacetate (DCFH-DA) assay in human skin fibroblasts.

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.

Extracellular alpha- and-beta-galactosidases from a strain of Aspergillus niger were separated and purified in one step by cation exchange chromatography. Both enzymes had acidic pH (3.5-4.0) and high temperature (65-degrees-C) optima and an exceptionally high thermostability. Thus, -alpha-galactosidase had an activity half-time of 104 min at 60-degrees-C whereas at the same temperature the respective value for-beta-galactosidase was 835 min. At optimum conditions of activity the apparent K(m) values of alpha- and beta-galactosidase were 0.44mM and 1.1mM respectively. Both the high temperature optima and thermostability properties of the enzymes make them particularly suitable for high temperature processes.

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%.

Fusarium oxysporum F3 produced N-acetyl-β-d-glucosaminidase when grown on wheat bran and chitin as carbon sources in solid-state fermentation. The initial moisture content and pH of growth medium were 65% and 6.0, respectively, and the enzyme yield 23.6 U g−1 carbon source. Two isozymes of N-acetyl-β-d-glucosaminidase, called N-acetyl-β-d-glucosaminidases I and II, were isolated from the culture filtrate of F. oxysporum F3. The filtrate was subjected to ammonium sulphate fractionation followed by anion exchange, gel filtration, hydrophobic interaction and cation exchange chromatography. The optimum pH of isozymes I and II was 5.0 and 6.0, respectively, whereas maximum activity of both isozymes was obtained at 40 °C. The Km of isozymes I and II was 49.6 and 48.6 μM and the Vmax 1.24 and 0.26 μmol mg−1 min−1, respectively, on p-nitrophenyl N-acetyl-β-d-glucosaminide as substrate. The molecular mass of isozymes I and II was calculated to be 67 kDa by SDS–PAGE.

Extracellular cellulolytic enzymes were produced under solid state cultivation by the thermophilic fungus Thermoascus aurantiacus and characterized. Elevated levels of endoglucanase and β-glucosidase activities were produced simultaneously by optimization of growth factors. Under optimal growth conditions, 1572 U endoglucanase and 101.6 U β-glucosidase per g of carbon source were obtained. Chromogenic (fluorogenic) 4-methylumbelliferyl-β-glycosides of glucose (MUG) and cellobiose (MUG2) were used to characterize the cellulolytic multienzyme components after separation by isoelectric focusing. The zymogram indicated one endoglucanase and one β-glucosidase with pI values 3.5 and 3.9, respectively. Both enzymes exhibited significant thermostability, with half-lives of 42 and 18 min, respectively, at 80°C

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.

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.

An intracellular beta-xylosidase from the thermophilic fungus Sporotricum thermophile strain ATCC 34628 was purified to homogeneity by Q-Sepharose and Mono-Q column chromatographies. The protein properties correspond to molecular mass and pI values of 45 kDa and 4.2, respectively. The enzyme is optimally active at pH 7.0 and 50 degrees C. The purified beta-xylosidase is fully stable at pH 6.0-8.0 and temperatures up to 50 degrees C and retained over 58% of its activity after 1 h at 60 degrees C. The enzyme hydrolyzes beta-1,4-linked xylo-oligosaccharides with chain lengths from 2 to 6, releasing xylose from the non-reducing end, but is inactive against xylan substrates. The apparent K-m and V-max values from p-nitrophenyl beta-D-xylopyranoside are 1.1 mM and 114 mu mol p-nitrophenol min(-1) mg(-1), respectively. Alcohols inactivate the enzyme, ethanol at 10% (v/v) yields a 30% decrease of its activity. The enzyme is irreversibly inhibited by 2,3-epoxypropyl beta-D-xylobioside while alkyl epoxides derived from D-Xylose were not inhibitors of the enzyme. The enzyme catalyses the condensation reaction using high donor concentration, up to 60% (w/v) xylose. (c) 2006 Elsevier Ltd. All rights reserved

Transaldolase (FoTal) was purified to homogeneity from the fungus Fusarium oxysporum. The native enzyme revealed a monomeric structure with molecular mass of 36 kDa. This FoTal depicted an optimal pH of 7.5 using imidazole buffer, while loss of activity was observed with Tris/HCl buffer. The optimal temperature was between 40 and 45 °C and the enzyme became unstable at temperatures above 50 °C. The isoelectric point of the purified enzyme was 4.5. The kinetics of the purified enzyme is consistent with a Ping Pong mechanism. The Km values for d-erythrose-4-phosphate and d-fructose-6-phosphate were 0.49 and 6.66 mM, while the kcat values were estimated at 4114 and 4151 min-1, respectively. LC-MS/MS analysis provided peptide mass and sequence information that facilitated primary structure confirmation, allowing us to identify the FoTal gene (foxg_03074) from the genome of F. oxysporum.

ATP-NADH kinase phosphorylates NADH to produce NADPH at the expense of ATP. The present study describes Fusarium oxysporum NADH kinase (ATP:NADH 2′-phosphotransferase, EC 2.7.1.86), a novel fungal enzyme capable of synthesizing NADPH using NADH as the preferred diphosphonicotinamide (diphosphopyridine) nucleotide donor. NADH kinase was highly purified (∼66-fold) and the enzyme was found to be a homodimeric with a subunit of M r 72,000. Isoelectric focusing in the pH range of 3.0-9.5 of the purified NADH kinase yielded a pI value of about 5.6. The K m values of NADH kinase for NADH and ATP were found to be 0.13 and 2.59 mM, respectively. Prediction of the secondary structure of the protein was performed in the PSIPRED server while modelling the three-dimensional (3D) structure was accomplished by the use of the HH 3D-structure prediction server

A number of factors affecting production of feruloyl esterase an enzyme that hydrolyse ester linkages of ferulic acid (FA) in plant cell walls, by the thermophylic fungus Sporotrichum thermophile under solid state fermentation (SSF) were investigated. Initial moisture content and type of carbon source were consecutively optimised. SSF in a laboratory horizontal bioreactor using the optimised medium allowed the production of 156 mU g−1 of carbon source, which compared favourably with those reported for the other micro-organisms. Optimal esterase activity was observed at pH 8 and 60 °C. The activity of the esterase was measured on an insoluble feruloylated hemicellulose substrate (de-starched wheat bran (DSWB)). De-esterification of wheat straw yielded loss of feruloyl esterase production even though the supplementation of free FA comparable to the alkali-extractable levels of FA found in wheat straw. Chromogenic (fluorogenic) 4-methylumbelliferyl ferulate was used to characterise the multienzyme component, after separation by isoelectric focusing and native PAGE electrophoresis. The zymograms indicated one major esterase activity exhibiting pI and molecular mass values 5 and 27 kDa, respectively.

Feruloyl esterases (FAEs) act synergistically with xylanases to hydrolyze ester-linked ferulic (FA) and diferulic (diFA) acid from cell wall material and therefore play a major role in the degradation of plant biomass. The potential applications of these enzymes with reference to agriculture. food and pharmaceutical industries, are discussed in this review. FAE activities produced by different microorganisms are compared for both submerged and solid state fermentations. In addition, their physicochemical properties and molecular biology are presented.

Two xylanases were purified to electrophoretic homogeneity from the thermophilic fungus Sporotrichum thermophile grown in a submerged liquid culture using wheat straw as carbon source. The enzymes, StXyn1 and StXyn2, have molecular masses of 24 kDa and 48 kDa, respectively, and are optimally active at pH 5 and at 60 °C. Both enzymes displayed remarkable stability up to 50 °C for 1 h, exhibiting a half-life of 60 min (StXyn1) and 115 min (StXyn2) at 60 °C. Biochemical characterization of the two xylanases against poly- and oligosaccharides indicated that StXyn1 and StXyn2 hydrolytic profiles match those of xylanase family 11 and family 10, respectively. LC-MS/MS analysis provided peptide mass and sequence information that assisted the identification of the corresponding xylanase genes from the S. thermophile genome and the classification of the two purified StXyn1 and StXyn2 as a family GH11 and GH10 endo-1,4-β-xylanases, respectively.