An olive oil-degrading bacterium strain N12 was isolated from soil and grown in mineral medium containing 0.2% olive oil as the sole carbon source. Physiologic, biochemical, and genetic analyses revealed that the strain belonged to the genus Acinetobacter. The strain N12 demonstarated lipase activity in the culture supernatant when cultivated under aerobic conditions in the oil-containing medium at 30°C. After incubating the strain in the medium for 24 h, n-hexane extract concentration in the culture medium decreased to 0.8% of the initial concentration ; this suggested that the strain could efficiently degrade the oil and fat (O/F). In addition, the strain was used in a grease trap system that had an inflow of restaurant wastewater. During the addition of the strain to the grease trap, the biochemical oxygen demand (BOD) values and n-hexane extract concentration in the treated remained low. This indicates that the strain also functions as an effective cleaner in such a practical systems as well as in the abovementioned flask test.
Coated steel sheets for exterior deteriorates with the combination of degradation of surface coatings by ultraviolet ray and heat and the corrosion of underneath steel sheets by water, salt, and cycles of dryness and moisture. In order to create the deterioration artificially, new cyclic-weathering test apparatus was invented. The apparatus repeatedly makes salt spray, wetting and ultraviolet ray irradiation with metal-halide lamp. Using the result of the cyclic weathering test, appropriate test conditions and evaluation items were determined. Then, according to the test conditions and evaluation items, five kinds of coated steel sheets for housing were tested. Each coated steel has different platting and paint. FinalIy, based on these results, we estimated the conditions of coated steel sheets used as roof sheets for 15 years and 30 years, and considered necessary measures such as re-painting.
The silicone rubber is often used as the piping tubes and the sealing gaskets for hot drink circuit in the beverage dispensers and the cup type vending machines. In such industrial equipments, the demand of market has become severe on the taste of beverage in recent years. Thus, ensuring the inertness of these silicone parts to the taste of beverage is the primal task. The silicone rubber tube is generally prepared by extrusion molding method. There are two kinds of rubbers : the organic peroxide cured and the platinum cured silicone rubbers are used for the extrusion molding. In the present study, effect of the post-processing treatments were investigated for the improvement of inertness properties of the silicone rubbers on the taste of beverage. A thorough postcure and following a hot water soaking treatment were found to have advantages for reducing the taste of both kinds of silicon rubbers.