The antibacterial efficiency of the methanolic extract of Phyllanthus niruri Linn. was investigated against pathogenic bacteria responsible for common infections of skin, and urinary and gastrointestinal tracts. The extract demonstrated antibacterial activities against all the Gram-positive and Gram-negative bacteria tested. The results obtained suggested that at higher concentrations the extract would eradicate the growth of bacterial cells. The bacterial cells, after exposure to the extract, showed complete alteration in their morphology, followed by collapse of the cells beyond repair. The study revealed that the methanolic extract of P. niruri may be an effective antibacterial agent to treat bacterial infections since the extract exhibited significant antimicrobial potency, comparable with that of the standard antibiotic chloramphenicol.
Aspergillus niger FETL FT3, a local extracellular tannase producer strain that was isolated from one of dumping sites of tannin-rich barks of Rhizophora apiculata in Perak, Malaysia. This fungus was cultivated in 250 mL Erlenmeyer flask under submerged fermentation system. Various physical parameters were studied in order to maximize the tannase production. Maximal yield of tannase production, that is, 2.81 U per mL was obtained on the fourth day of cultivation when the submerged fermentation was carried out using liquid Czapek-Dox medium containing (percent; weight per volume) 0.25% NaNO(3), 0.1% KH(2)PO(4), 0.05% MgSO(4) ·7H(2)O, 0.05% KCl, and 1.0% tannic acid. The physical parameters used initial medium pH of 6.0, incubation temperature of 30°C, agitation speed of 200 rpm and inoculums size of 6 × 10(6) spores/ ml. This research has showed that physical parameters were influenced the tannase production by the fungus with 156.4 percent increment.
A total of 34 bacterial isolates were obtained from soil samples collected from Changar Hot Spring, Malang, Indonesia. Of these, 13 isolates produced a zone of hydrolysis in starch-nutrient agar medium and generated various amylases in liquid medium. One isolate was selected as the best amylase producer and was identified as Bacillus licheniformis BT5.9. The improvement of culture conditions (initial medium pH of 5.0, cultivation temperature of 50°C, agitation speed of 100 rpm and inoculum size of 1.7 × 10(9) cells/ml) provided the highest amylase production (0.327 U/ml).