[Establishment of a genetic transformation system for Penicillium brevicompactum to produce mycophenolic acid].

OBJECTIVE: We established a genetic transformation system for Penicillium brevicompactum to produce mycophenolic acid. METHODS: We developed protoplast transformation methods mediated by Polyethylene glycol, using phleomycin resistance gene (Sh ble) as a dominant selection marker. RESULT: The frequency of transformation was up to 2 - 3 transformants per microg DNA; analysis of the transformants by PCR showed that the foreign DNA had been integrated into the host genome. The transformants retained stable after generation. CONCLUSION: The establishment of the genetic transformation system of Penicillium brevicompactum could serve as the basis for the research of molecular biology and the breeding of gene engineering of the fungus.

Adsorption of heavy metal ions using hierarchical CaCO3-maltose meso/macroporous hybrid materials: adsorption isotherms and kinetic studies.

Highly ordered hierarchical calcium carbonate is an important phase and has technological interest in the development of functional materials. The work describes hierarchical CaCO(3)-maltose meso/macroporous hybrid materials were synthesized using a simple gas-diffusion method. The uniform hexagonal-shaped CaCO(3)-maltose hybrid materials are formed by the hierarchical assembly of nanoparticles. The pore structure analysis indicates that the sample possesses the macroporous structure of mesoporous framework. The distinguishing features of the hierarchical CaCO(3)-maltose materials in water treatment involve not only high removal capacities, but also decontamination of trace metal ions. Langmuir model fitted the equilibrium data better than the Freundlich isotherm. The maximum removal capacity of the CaCO(3)-maltose hybrid materials for Pb(2+), Cd(2+), Cu(2+), Co(2+), Mn(2+) and Ni(2+) ions was 3242.48, 487.80, 628.93, 393.70, 558.66 and 769.23 mg/g, respectively. Adsorption data were modeled using the pseudo-first-order, pseudo-second-order and intra-particle diffusion kinetics equations. The results indicate that pseudo-second-order kinetic equation and intra-particle diffusion model can better describe the adsorption kinetics. The adsorption and precipitation transformation mechanism can be considered due to hierarchical meso/macroporous structure, rich organic ligands of the CaCO(3)-maltose hybrid materials and the larger solubility product of CaCO(3).

Molecular cloning and functional identification of a novel phenylacetyl-CoA ligase gene from Penicillium chrysogenum.

A novel phenylacetyl-CoA ligase gene, designated phlB, was cloned and identified from the penicillin producing strain Penicillium chrysogenum based on subtractive suppression hybridization approach. The phlB gene contains a 1686-bp open-reading frame and encodes a protein of approximately 62.6 kDa. The deduced amino acid sequence shows about 35% identity to the characterized P. chrysogenum phenylacetyl-CoA ligase Phl and has a peroxisomal targeting signal on its C-terminal. Recombinant PhlB protein was overexpressed in Escherichia coli and purified by nickel affinity chromatography. Enzymatic assay confirmed that recombinant PhlB can catalyze the reaction of phenylacetic acid (PAA) with CoA to yield phenylacetyl-CoA. The expression level of phlB in the penicillin producing medium supplemented with PAA, the side chain precursor of penicillin G, was about 2.5-fold higher than that in medium without PAA. The study suggested that PhlB might participate in the activation of PAA during penicillin biosynthesis in P. chrysogenum.