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Of fourteen natural isolates of Trichoderma, no correlation was found between substrate weight loss and phenol oxidase (PO) activity in rice straw cultures. The highest PO producer from these laccase-positive strains was subjected to UV mutagenesis in order to select high and low PO activity mutants. There was no significant difference in substrate weight loss for mutant strains with six times higher and six times lower PO activity than the parent strain. Nor did the enzyme activity result in decreased growth inhibition by inhibitory phenolic compounds. PO enzyme from the parent Trichoderma and one of its high-PO-activity mutants was subsequently purified by ethanol precipitation from liquid cultures optimized by supplementation with copper sulphate and cycloheximide. Protein staining and activity staining of disc electrophoresis gels showed that only one PO enzyme of approximately 71000 Da was produced. The enzyme could be defined as a laccase (benzenediol: oxygen oxidoreductase E.C. 1.10.3.2) because it catalysed the oxidation of syringaldazine and p-phenylenediamine in the absence of hydrogen peroxide, and because it was inhibited by cetyltrimethylammonium bromide but not by cinnamic acid. No specific in-vivo function could be assigned to this enzyme.

In this study, we developed and investigated nanoparticles of biologically-derived, biodegradable polyhydroxyalkanoates (PHAs) as carriers of a hydrophobic photosensitizer, 5,10,15,20-Tetrakis(4-hydroxy-phenyl)-21H, 23H-porphine (pTHPP) for photodynamic therapy (PDT). Three PHA variants; polyhydroxybutyrate, poly(hydroxybutyrate-co-hydroxyvalerate) or P(HB-HV) with 12 and 50% HV were used to formulate pTHPP-loaded PHA nanoparticles by an emulsification-diffusion method, where we compared two different poly(vinyl alcohol) (PVA) stabilizers. The nanoparticles exhibited nano-scale spherical morphology under TEM and hydrodynamic diameters ranging from 169.0 to 211.2 nm with narrow size distribution. The amount of drug loaded and the drug entrapment efficiency were also investigated. The in vitro photocytotoxicity was evaluated using human colon adenocarcinoma cell line HT-29 and revealed time and concentration dependent cell death, consistent with a gradual release pattern of pTHPP over 24 h. This study is the first demonstration using bacterially derived P(HB-HV) copolymers for nanoparticle delivery of a hydrophobic photosensitizer drug and their potential application in PDT.

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Solid-state fermented Thai rice wines (Ou) were analysed to determine their chemical components. Determined parameters were pH (4.5-5.5), protein (0.45-0.99 g/100g), ash (0.10-0.30 g/100g), total solid (1.72-14.34 g/100g), glucose (4.07-7.91 mg/ml) contents and volatile compounds. The ethanol concentration was in the range of 12.15 to 104.60 mg/ml. Profiles of volatile compounds were analysed by dynamic headspace coupled with gas chromatography mass spectrometry and gas chromatography olfactometry. The potent odours were alcoholic and solvent-like, sweet, fruity, buttery, and pungent aromas. The concentration in Ou of n-propanol, iso-butyl alcohol, iso-amyl alcohol, furfuryl alcohol, benzene ethanol, acetol, 2,3-butanediol, glycerol, ethyl lactate, acetoin, furfural, 5-methyl furfural, 5-hydroxymethyl-2-furfural, and acetic acid were also determined by a direct injection technique. From principal component analysis, Ou samples could be categorized into two groups based on the concentration of ethanol and their profiles of volatile compounds.