The earth-star basidiomycetous mushroom Astraeus odoratus produces polyhydroxyalkanoates during cultivation on malt extract.

Polyhydroxyalkanoates (PHAs) including poly-3-hydroxybutyrate (P3HB) as secondary metabolisms were in vitro produced by the edible basidiomycetous mushroom Astraeus odoratus during its growth on malt agar extract. Various carbon and nitrogen sources containing cellulose, glucose, glycerol, rice straw powder, soybean meal and peptone were investigated for the growth of basidiomycetous mushrooms. During cultivation, the A. odoratus culture exudated the considerably extracellular fluid up to approx. 2.3 ml on 2% malt extract agar plate within 7 days. The chemical compounds of the exudated fluid were further investigated by Fourier-transform infrared spectroscopy (FTIR) and gas chromatography/mass spectrometry (GC/MS); and its morphology of the lyophilized sample was observed by scanning electron microscope (SEM). FTIR results showed the characteristic bands of OH at 3445 cm-1, CH/CH2/symmetric CH3 (stretch) at 2923 and 2852 cm-1, C=O at 1730 cm-1, asymmetric CH3 (bend) at 1454 and 1414 cm-1, C-O of COO- at 1396 cm-1 and C-O-C at 1223, 1160, 1116, 1058 and 1019 cm-1 which were similar to the absorptive characteristics of P3HB. Methyl ester derivatives of GC/MS results identified 7 compounds including: 3-hydroxybutanoic (monomer of PHB), aminobenzoic, salicylic, hexadecenoic, octadecadienoic, octadecenoic and octadecanoic acids. SEM images revealed a fibriform and porous materials. Hence, the occurrence of PHAs was first described in a basidiomycetous mushroom A. odoratus. Thus, PHAs could be found not only in bacteria and but also in basidiomycetous mushroom, which can be promising target for bioplastics and green environmental studies.

Antimicrobial and Antioxidant Activity of the Polypore Mushroom Lentinus arcularius (Agaricomycetes) Isolated in Vietnam.

Lentinus arcularius (=Polyporus arcularius) is a medicinal polypore mushroom recorded in Vietnam based on morphological observation. In this study, three L. arcularius isolates were identified using molecular and morphological methods. Furthermore, the antimicrobial and antioxidant activities of their intracellular and/or extracellular metabolites were investigated. The ethyl acetate and n-butanol fractions were the most active extracts against Gram-positive and Gram-negative bacteria (Escherichia coli VTCC 12014, Pseudomonas aeruginosa VTCC 12273, and Staphylococcus aureus VTCC 10658) and fungi (Candida albicans VTCC 20568, Saccharomyces cerevisiae VTCC 20146, and Aspergillus niger VTCC 30001). These fractions also showed the highest antioxidant activity by α,α-diphenyl-ß-picryl-hydrazyl as a free-radical agent or the highest percentage at 75-100% inhibition. These results suggest that L. arcularius might be a potential medicinal mushroom with antimicrobial and antioxidant effects.

The production of ß-glucosidases by Fusarium proliferatum NBRC109045 isolated from Vietnamese forest.

Fusarium proliferatum NBRC109045 is a filamentous fungus isolated from Vietnamese forest due to high production of ß-glucosidases. Production of the enzyme was studied on varied carbon source based mediums. The highest activity was obtained in medium containing 1% corn stover + 1% wheat bran (3.31 ± 0.14 U/ml). It is interesting to note that glucose (0.69 ± 0.02 U/ml) gave higher activity and just followed by cellobiose among the di- and mono-saccharides, which is generally regarded as a universal repressor of hydrolases. We improved the zymogram method to prove that in response to various carbon sources, F. proliferatum could express various ß-glucosidases. One of the ß-glucosidases produced by F. proliferatum growing in corn stover + wheat bran based medium was partially purified and proved to have high catalytic ability.