碩士 / 國立海洋大學 / 食品科學系 / 87 / Abstract
Substrata of wood, fiber-reinforced plastic (FRP), steel and glass were immersed in seawater under 1 meter of sea level at the seashores of Pa-Zhi-Men and Keelung Isle. The amounts and flora of the attached fungi on these substrata were investigated. The temperature, pH value and dissolved oxygen of seawater from these two different experimental areas were similar, which were in the ranges of 17~25oC, 8.1~8.5 and 7.5~8.2 ppm, respectively. However, higher fungal content was found in seawater at Pa-Zhi-Men. The total organic contents in seawater at Pa-Zhi-Men and Keelung Isle were 494 and 337 ppm, respectively; while ammonium nitrogen contents being 0.57 and 0.37, respectively. The effects of location and season on the fungal attachment were found. Higher counts of attached fungi were obtained at Pa-Zhi-Men than at Keelung Isle. Higher fungal counts were observed in winter than in summer. The effect of the types of substrata on the fungal attachment was various with season. The fungal flora on the tested substrata was similar. The attached yeast isolates were included in the genera of Candida, Rhodotorula, Cryptococcus, Trichosporon, Pichia, Klosckera, Saccharomyces and Debaryomyces. The identified mold isolates were mainly in the genera of Penicillium、Geotrichum、Mucor、Aspergillus、Fusarium、Trichoderma and Cladosporium. Three fungal isolates, Candida humicola 423, Candida guilliermondii 379 and Debaryo polymorphus 471, were chosen as the tested microorganisms due to their high adhesive capability among 269 fungal isolates. In addition, one strain of Rhodotorula rubra 091 was also tested due to its high incidence on the substrata. Their proliferation in seawater and the environmental factors of seawater, such as carbon and nitrogen, salt contents, pH value and temperature, on the growth and attachment on glass slide were investigated. These 4 isolates could proliferate by 100-1000 times and survived over 110 days in seawater. Temperature in the ranges of 20-37oC and pH value (6-9) did not affect their growth and adhesive capability. The effects of carbon sources and nitrogen sources in seawater varied with the tested isolates. In general, the addition of 0.5% various carbon sources obviously decrease the fungal attachment. 0.1% cellulose, casein or KNO3 in seawater stimulated yeast adhesion. Cations of Ca2＋ and Mg2＋ also showed positive effects for fungal attachment. The co-existence of yeast C. guilliermondii and bacterium Pseudomonas cepacia did not affect their individual adhesive ability. However, the pre-existence of bacteria on glass slide decreased the adhesive ability of yeast. The bacterial attachment was similar, irrespective of the presence of yeast. When C. guilliermondii and D. polymorphus were cultivated in brain heart infusion broth (BHIB), the cell surface hydrophobicity, measured by microbial adhesion to hydrocarbon method (MATH), and adhesive ability increased with increasing of cell age. However, the surface hydrophobicity and adhesive ability of C. guilliermondii and R. rubra decreased as their cell ages increased. On the other hand, the cell surface hydrophobicity of C. guilliermondi in seawater gradually decreased and became very small; however, its adhesive ability increased. This demonstrated that the factor of the cell surface charge may become the determinant factor for the attachment of yeast in seawater.
| Identifer | oai:union.ndltd.org:TW/087NTOU0253026 |
| Date | January 1999 |
| Creators | Wu Wen-Ching, 吳文菁 |
| Contributors | Tsai Guo-Jane, 蔡國珍 |
| Source Sets | National Digital Library of Theses and Dissertations in Taiwan |
| Language | zh-TW |
| Detected Language | English |
| Type | 學位論文 ; thesis |
| Format | 84 |
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