Combined photo-assisted and biological treatment of industrial oily wastewater.

In the present study an oily wastewater from the lubricant unit of a petroleum company was evaluated by combining the sequence photo-assisted oxidation-Pseudomonas putida DSM 437. The wastewater contained various alcohols, acids and phenolic compounds. From the above mentioned compounds the biodegradation of ethylene glycol, phenol, o-cresol and p-cresol was examined. The direct biodegradation of the wastewater using P. putida DSM 437 resulted in 85% ethylene glycol assimilation while phenol, o-cresol and p-cresol assimilation was in the range of 27% to 40%. In order to increase the degradation of the phenolic compounds photo-assisted oxidation was applied to the wastewater using UV/ H2O2 its a pretreatment step to biological degradation. Fc(III) were used in order to accelerate the formation of the hydroxyl radicals and consequently the overall photo-oxidation process. The addition of Fe(III) ions resulted in 30% decrease of COD within the first 10 min while the respected value without iron ions was 5%. The combined photo-assisted oxidation and biodegradation of the wastewater resulted in 100% removal of ethylene glycol. The overall degradation of phenol was 78% while the 59% and 84% of the initial o-cresol and p-cresol respectively, were removed from the wastewater. The combined process resulted in 72% of COD removal.

Induction, purification, and characterization of two extracellular alpha-L-arabinofuranosidases from Fusarium oxysporum.

In the presence of L-arabinose as sole carbon source, Fusarium oxysporum produces two alpha-L-arabinofuranosidases (ABFs) named ABF1 and ABF2, with molecular masses of 200 and 180 kDa, respectively. The two F. oxysporum proteins have been purified to homogeneity. The purified enzymes are composed of three equal subunits and are neutral proteins with pIs of 6.0 and 7.3 for ABF1 and ABF2, respectively. With p-nitrophenyl alpha-L-arabinofuranoside (pNPA) as the substrate, ABF1 and ABF2 exhibited Km values of 0.39 and 0.28 mmol.L(-1), respectively, and Vmax values of 1.6 and 4.6 micromol.min(-1).(mg of protein)(-1), respectively, and displayed optimal activity at pH 6.0 and 50-60 degrees C. ABFs released arabinose only from sugar beet arabinan and not from wheat soluble and insoluble arabinoxylans. The enzymes were not active on substrates containing ferulic acid ester linked to C-5 and C-2 linkages of pNPA showing that phenolic substituents of pNPA sterically hindered the action of ABFs.

Biochemical and catalytic properties of an endoxylanase purified from the culture filtrate of Sporotrichum thermophile.

An endo-beta-1,4-xylanase (1,4-beta-D-xylan xylanoxydrolase, EC 3.2.1.8) present in culture filtrates of Sporotrichum thermophile ATCC 34628 was purified to homogeneity by Q-Sepharose and Sephacryl S-200 column chromatographies. The enzyme has a molecular mass of 25,000 Da, an isoelectric point of 6.7, and is optimally active at pH 5 and at 70 degrees C. Thin-layer chromatography (TLC) analysis showed that endo-xylanase liberates mainly xylose (Xyl) and xylobiose (Xyl2) from beechwood 4-O-methyl-D-glucuronoxylan, O-acetyl-4-O-methylglucuronoxylan and rhodymenan (a beta-(1-->4)-beta(1-->3)-xylan). Also, the enzyme releases an acidic xylo-oligosaccharide from 4-O-methyl-D-glucuronoxylan, and an isomeric xylotetraose and an isomeric xylopentaose from rhodymenan. Analysis of reaction mixtures by high performance liquid chromatography (HPLC) revealed that the enzyme cleaves preferentially the internal glycosidic bonds of xylooligosaccharides, [1-3H]-xylooligosaccharides and xylan. The enzyme also hydrolyses the 4-methylumbelliferyl glycosides of beta-xylobiose and beta-xylotriose at the second glycosidic bond adjacent to the aglycon. The endoxylanase is not active on pNPX and pNPC. The enzyme mediates a decrease in the viscosity of xylan associated with a release of only small amounts of reducing sugar. The enzyme is irreversibly inhibited by series of omega-epoxyalkyl glycosides of D-xylopyranose. The results suggest that the endoxylanase from S. thermophile has catalytic properties similar to the enzymes belonging to family 11.

Enzymic production of a feruloylated oligosaccharide with antioxidant activity from wheat flour arabinoxylan.

BACKGROUND: Main cereals such as rice, wheat, barley, and corn belong to the family Gramineae and have similar cell-wall composition. Since cereal cell walls are a good source of dietary fibre, meeting one-half of the daily requirement of 30 g of dietary fibre can be achieved by the regular consumption of cereals. Many studies have dealt with the isolation of feruloylated oligosaccharides from Gramineae by treatment with polysaccharide hydrolysing enzymes. AIM OF THIS STUDY: Therefore, the purpose of this study was to investigate the production of feruloylated oligosaccharides from insoluble wheat flour arabinoxylan (WFAX) by treatment with a Thermoascus aurantiacus family 10 endoxylanase (XYLI) and the evaluation of their antioxidant activity. METHODS: The main feruloylated oligosaccharide was purified by anion-exchange and size-exclusion chromatography (SEC). Alkaline saponification and acid hydrolysis were used for product identification. Evaluation of antioxidant activity was performed by the 2,2-diphenyl-1-picrylhydrazyl (DPPH) reduction assay and the inhibition of copper-mediated oxidation of low density lipoprotein (LDL). RESULTS: The optimal conditions for WFAX hydrolysis using the XYLI have been determined to be 100 U g(-1) of WFAX for 30 min at 50 degrees C. Saponification of the oligosaccharide released FA and oligosaccharide. The released oligosaccharide consisted of arabinose and xylose in a molar ratio of 1:3 and these results support the identity of the feruloylated oligosaccharide as feruloyl arabinoxylotrisaccharide (FAX(3)). FAX(3) showed profound antioxidant activity in 2,2-diphenyl-1-picrylhydrazyl (DPPH) reduction assay exhibiting an antiradical efficiency of 0.035 (x 10(-3)) and inhibited the copper-mediated oxidation of human low density lipoprotein (LDL) in a dose-dependent manner with almost complete inhibition at 32 microM. CONCLUSION: A feruloylated oligosaccharide (FAX3) was isolated from WFAX after enzymatic treatment with XYLI. We verified antioxidant activity of FAX(3) which may be important in preventing or reducing the progression of atherosclerosis by inhibiting the peroxidation of lipoproteins.

Enzymic production of aldopentauronic acid and use as a bioregulator in plant airlift bioreactors.

Neutral and acidic oligosaccharides were obtained from birchwood xylan by treatment with an endoxylanase, family 11 class, from Sporotrichum thermophile. The main acidic xylooligosaccharide (aldopentauronic acid) was separated from the hydrolysate by anion-exchange and size-exclusion chromatography and the structure was determined by 13C NMR spectroscopy. The aldopentauronic acid yield was 25% (w/w) of the total solubilized sugars. The addition of purified aldopentauronic acid at a concentration of 5 mg/l to cucumber liquid culture in 2.5-l airlift bioreactors caused in increase in both the number of regenerants and their fresh weight.