Browsing by Author "Nakamura, Y."

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    Lignocellulosic Enzymes from Flavodon Flavus, a Fungus Isolated from Western Indian Ocean off the Coast of Dar es Salaam, Tanzania
    (2008-07) Mtui, Godliving Y. S.; Nakamura, Y.
    Marine basidiomycetes fungus Flavodon flavus (Klotzsch) Ryvarden was isolated from sea grass at Mjimwema in the Western Indian Ocean off the Coast of Dar es Salaam, Tanzania, and cultured in the laboratory. Protein content and lignocellulosic enzyme activities were measured by photometric methods. Desalted and size-separated enzyme filtrates were resolved by sodium docecyl sulphatepolyacrylamide gel electrophoresis (SDS-PAGE) and isoelectric focusing (IEF). The fungal filtrate had maximum lignin peroxidase (LiP), manganese peroxidase (MnP) and Laccase (Lac) activities of 42, 25 and 15 U/mL, respectively. At low carbon medium, F. flavus showed effective (92 - 100%) decolorization of raw textile wastewater and synthetic dyes such as rhemazol brilliant blue-R (RBB-R), Brilliant green, Congo red, Reactive black and Reactive yellow. SDS-PAGE analysis showed major bands of sizeseparated enzymes from F. flavus at relative molecular weights between 45 and 70 kDa. The LiP of F. flavus, purified by ion exchange chromatography, revealed that it has a molecular weight of 46 kDa and isoelectric point (pI) of 3.8. The study confirmed extracellular enzymes from F. flavus to be potential degraders of organic pollutants and showed that facultative marine fungi that live under harsh seawater conditions are suitable for bioremediation of recalcitrant environmental pollutants.
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    Microbial Treatment of Kraft Pulp Wastewater Pretreated with Ozone
    (1997-02) Nakamura, Y.; Sawada, T.; Kobayashi, F.; Mtui, Godliving Y. S.
    Kraft pulp wastewater was treated with a combination of ozone and activated sludge. The effects of pH on the degradation of lignin and the production of organic acids were examined experimentally in the ozonolysis of wastewater. The strong alkaline condition enhanced not only the degradation of lignin but also the production of organic acids. The dynamic behaviours of microbial growth and substrate consumption were investigated in the biodegradation of organic acids using activated sludge. Maleic acid and oxalic acid in the ozonized wastewater were degraded completely by the activated sludge. The immobilized activated sludge culture using polyurethane foam was effective in degrading organic acids.