Purification and characterization of a β-glucosidase from aspergillus niger and its application in the hydrolysis of geniposide to genipin.

An extracellular β-glucosidase from Aspergillus niger Au0847 was purified to homogeneity by precipitation with ammonium sulfate, anion exchange, and gel filtration. The purified protein was composed of two subunits with molecular masses of 110 and 120 kDa. Au0847 β-glucosidase exhibited relatively high thermostability and pH stability, and its highest activity was obtained at 65°C and pH 4.

Morphology engineering of Penicillium chrysogenum by RNA silencing of chitin synthase gene.

Chitin synthases, that catalyze the formation of chitin the major component of cell walls in most filamentous fungi, play crucial roles in the growth and morphogenesis. To investigate the roles of chitin synthase in Penicillium chrysogenum, we developed an RNAi system to silence the class III chitin synthase gene chs4. After transformation, mutants had a slow growth rate and shorter but highly branched hyphae.

Morphological changes induced by class III chitin synthase gene silencing could enhance penicillin production of Penicillium chrysogenum.

Chitin synthases catalyze the formation of β-(1,4)-glycosidic bonds between N-acetylglucosamine residues to form the unbranched polysaccharide chitin, which is the major component of cell walls in most filamentous fungi. Several studies have shown that chitin synthases are structurally and functionally divergent and play crucial roles in the growth and morphogenesis of the genus Aspergillus although little research on this topic has been done in Penicillium chrysogenum. We used BLAST to find the genes encoding chitin synthases in P.

Characterization of bioimprinted tannase and its kinetic and thermodynamics properties in synthesis of propyl gallate by transesterification in anhydrous medium.

Tannase has been extensively applied to synthesize gallic acid esters. Bioimprinting technique can evidently enhance transesterification-catalyzing performance of tannase. In order to promote the practical utilization of the modified tannase, a few enzymatic characteristics of the enzyme and its kinetic and thermodynamics properties in synthesis of propyl gallate by transesterification in anhydrous medium have been studied.

[Induced synthesis of hydroxyapatite by Aspergillus niger].

Objective: The research objective is to induce hydroxyapatite (HAP) synthesis by using fungus.

Methods: We used the PDA (Potato Dextrose Agar Medium) liquid medium containing different concentrations of Na2HPO4 and CaCO3 to study the way Aspergillus niger synthesize HAP, to observe the induced mineral crystal structure and to analyze the induced mineral type with transmission electron microscopy (TEM) and X-ray diffraction (XRD).

Results: The main results are as follows: (1) A.

Status, ecology, and conservation of the Himalayan griffon Gyps himalayensis (Aves, Accipitridae) in the Tibetan plateau.

The dramatic population crashes of 3 species of Gyps vulture have raised concerns about the status of their lesser-known congeners. Among these is the Himalayan griffon, G. himalayensis, an iconic vulture of the Tibetan plateau.