The Optimization of Aspergillus sp.GM4 Tannase Production under Submerged Fermentation

Tannase is a hydrolytic enzyme that is involved in the biodegradation of tannins and it has biotechnological potential in the pharmaceutical, chemical, food and beverage industries. Microorganisms, especially filamentous fungi, are important tannase producers. The aims of this work were to find a potential tannase producer and to improve the cultivation conditions. Three Aspergillus species (A. japonicus 246A, A. tamarii 3 and Aspergillus sp. GM4) were investigated in different culture media (Adams, Czapeck, Khanna, M5 and Vogel) and inducers (1% and 2% tannic acid;1% green tea;1% methyl gallate;1% gallic acid). Aspergillus sp. GM4 and Adams medium were selected. The tannase production by Aspergillus sp. GM4 in Adams medium was induced in the presence of 2% (w/v) tannic acid and gallic acid as carbon sources, while green tea was not able to induce tannase production. The Plackett-Burman screening design was performed with the variables MgSO4, KH2PO4, yeast extract, tannic acid, agitation rate and salt solution. The variables MgSO4 and agitation rate were selected for the optimization of tannase production using a Central Composite Rotatable Design. Under optimized conditions, a 2.66-fold increase in the enzyme production was observed with small modifications in the medium composition.

Characterization and Biological Activities of Protein-Bound Polysaccharides Produced by Cultures of Pleurotus ostreatus

Several species of mushrooms, as Pleurotus ostreatus, have been valued as edible and medicinal resources. These mushrooms may be an important source of polysaccharides with medicinal properties as antioxidant, antitumoral, antimicrobial and immunological properties. The aim of this work was to produce and to evaluate the biological properties of protein-bound polysaccharide complexes, extra intracellular （E-PPS and I-PPS）, extracted from P. ostreatus cultures, using agricultural sunflower wastes as carbon source. Three main compounds in the E-PPS and four main compounds in the I-PPS were identified by SEC-UV-RI-HPLC. These complexes of P. ostreatus present no toxicity in Artemia salina cultures, after 24 h of incubation. Antioxidant properties of the complexes were evaluated by radical scavenging activity using DPPH method and lipid peroxidation inhibition capacity, determined by erytbsocytes hemolysis. Additionally, E-PPS and I-PPS extracts revealed capacity to mimetize superoxide dismutase and catalase enzymatic activities. The hepatoprotector effect of E-PPS extracts in Wistar rats was evaluated by AST, ALT, ALP and y-GT activities, showing capacity to reduce the liver damage induced by ethanol-administration. This hepatoprotective effect is equivalent to that observed by silymarin, a standard drug. Our results suggests that the extracts of E-PPS and I-PPS produced by P. ostreatus cultures, using agricultural sunflower wastes as main carbon source, can be used as an important source of bioactive compounds with potential medicinal value.

Endophytic mycobiota of wild medicinal plants from New Valley Governorate,Egypt and quantitative assessment of their cell wall degrading enzymes

The present study isolated and identified 32 species of endophytic mycobiota belonging to 18 genera associated with 8 wild medicinal plants collected from El-Kharga Oasis,New Valley Governorate,Egypt.Fusarium was the most common genus followed by Alternaria and Aspergillus.Convolvulus arvensis was the plant with the highest number of endophytes over the other plant species,while Moringa oleifera reported the lowest number of endophytes.In addition,the entomopathogenic fungus Beauveria bassiana;was recorded for the first time from leaves of Portulaca oleracea.One hundred and twenty-three isolates representing 32 species were screened for their abilities to produce pectinase,carboxy methyl cellulase(CMCase)and avicellase enzymes on sucrose free-Cz supplemented,individually with 1%pectin or 1%CMC or 1%avicel as a sole carbon source,respectively.Ninety-four isolates produced pectinase while 66 isolates produced cellulases.The quantitative assays of the three enzymes for high-producers were performed in submerged fermentation using sucrose-free Cz broth.Aspergillus was the superior in the production of the three enzymes with the potent strains were A.terreus AUMC 14287 for CMCase(22.0 IU/ml/min)and avicellase(47.868 IU/ml/min)and A.terreus AUMC 14278 for pectinase(225.43 IU/ml/min).