Production, purification, and determination of the biochemical properties of ß-glucosidase in Trichoderma koningii via solid substrate fermentation.

The ß-glucosidase enzyme was obtained from Trichoderma koningii Oudem. NRRL 54330 under optimal conditions by solid substrate fermentation (SSF) using corn cobs as substrate. The enzyme was purified by two-step procedures, ammonium sulphate precipitation and cefarose-4B-l-tyrosine-1-naphthylamine hydrophobic interaction chromatography, followed by biochemical and kinetic characterisation. The ß-glucosidase was obtained from T. koningii using ground corn cob as substrate and Na2HPO4, pH 9, as humidification medium. The optimum conditions for enzyme production by SSF were 30 °C and 6 days. The purification efficiency of the obtained ß-glucosidase was calculated to be 22.56-fold with a yield of 73.51 %. In the determination of ß-glucosidase activity, p-nitrophenyl-ß-d-glucopyranoside (pNPG) substrate was used, and the optimum pH and temperature values at which ß-glucosidase showed high activity were determined to be pH 3.0 and 75 °C. The purity of the enzyme and the presence/number of subunits were checked using two different electrophoretic methods, SDS-PAGE and NATIVE-PAGE electrophoretic methods. The K m and V max values of the purified enzyme were determined to be 0.16 mM and 2000 EU respectively. It was also found that d-(+)-glucose and δ-gluconolactone inhibitors exhibited competitive inhibition of ß-glucosidase in the presence of pNPG.

Essential oil chemical composition, antimicrobial, anticancer, and antioxidant effects of Thymus convolutus Klokov in Turkey.

In this study, the chemical composition, antimicrobial, antioxidant, and anticancer effects of Thymus convolutus Klokov oil and its main compound camphor were investigated. The oil was isolated from T. convolutus using hydrodistillation method, analyzed by gas chromatography/mass spectrometry (GC-MS), and 66 compounds were identified. The main component was determined as camphor at 16.6%. The antioxidant properties were identified with the DPPH (2,2'-diphenyl-1-picrylhydrazyl) radical-scavenging method and, 33.39 ± 0.25% DPPH was scavenging in 1000 µg/mL of essential oil. The strong antimicrobial activity was observed against Escherichia coli, Enterobacter aerogenes, Proteus vulgaris, and Pseudomonas aeruginosa with MIC values of 125 µg/mL. Aspergillus flavus was more sensitive (28%) against T. convolutus essential oil than other fungi. The cytotoxic effect of oil was analyzed by MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide) method. Camphor was effective on human hepatoma cells (Hep3B) at concentrations of 1 mg/mL, 500, 250, and 125 µg/mL, while essential oil of T. convolutus was found to be effective at concentrations of 250 and 125 µg/mL. A reduction in cell proliferation was observed in colon carcinoma cells (HT-29) treated with 500 µg/mL camphor for 48 h. No statistically significant effect was found in Umbilical Vein Endothelial Cells (HUVEC) treated with essential oil and camphor.