從喀麥隆先前沒(méi)有被石油烴污染的土壤樣品中分離獲得一株柴油降解酵母KML。根據(jù)其形態(tài)特征,生理生化特性和5.8S rDNA-ITS基因序列分析,這株酵母菌被認(rèn)定為解脂耶羅維亞酵母菌(Yarrowia lipolytica)。通過(guò)單因素變量法研究各種因素對(duì)這株菌降解能力的影響。結(jié)果顯示：在20、30、37℃三種不同溫度下測(cè)試其降解率,30℃為最適溫度,約有59.0%的柴油被降解。通過(guò)不同的最初pH測(cè)試(分別為6、7、8、9和10),最適最初pH值為9,約75.1%的柴油被降解。培養(yǎng)基中不同的氮源對(duì)KML柴油降解率影響試驗(yàn)影響結(jié)果顯示：濃度為1mg/ml的酵母提取物為最好的氮源,降解的柴油為76.8%；培養(yǎng)基中添加濃度為10mg/ml的鼠李糖作為生物表面活性劑的情況下KML柴油降解率最高可達(dá)到78.0%。 不同的生物接種量也影響到KML降解率。接種量分別為7×106、3.8×107、4.7×108和2.8×109cells/ml情況下,其對(duì)應(yīng)的柴油降解率分別為66.1,61.2,55.1和54.0%。分離菌株在含濃度為10%-5%柴油的培養(yǎng)基中均能降解柴油。 氣相色譜-質(zhì)譜法(GC-M...

【文章頁(yè)數(shù)】：88 頁(yè)

【學(xué)位級(jí)別】：碩士

【文章目錄】：
摘要
ABSTRACT
Chapter 1 Literature review
    1.1 Use of petroleum and its products
    1.2 Components in crude oil or petroleum
    1.3 Environmental issues of petroleum
    1.4 Methods to clean up petroleum
        1.4.1 Mechanical method
        1.4.2 Chemical method
        1.4.3 Physical method
        1.4.4 Biological method
    1.5 Microorganims degrading petroleum hydrocarbons
    1.6 Mechanisms of hydrocarbons biodegradation
    1.7 Factors affecting the biodegradation
        1.7.1 Physical state of oil
        1.7.2 Temperature
        1.7.3 Nutrients
        1.7.4 Others factors
    1.8 Presentation of Cameroon and objectives of this work
        1.8.1 Cameroon
        1.8.2 Objectives and scope of this study
        1.8.3 Plan of the thesis
    References
Chapter 2 Isolation and identification of diesel degrading microorganisms
    2.1 Introduction
    2.2 Materials
        2.2.1 Microorganisms source
        2.2.2 Medium and reagents
            2.2.2.1 Media
            2.2.2.2 Reagents
        2.2.3 Main reagents
        2.2.4 Equipments
    2.3 Methods
        2.3.1 Isolation of microorganisms
        2.3.2 Screening of diesel oil degrading microorganisms
        2.3.3 Identification of the isolate
            2.3.3.1 Morphological characteristics of colonies on the plate
            2.3.3.2 Microscopic appearance of cells
            2.3.3.3 Physiological and biochemical tests
            2.3.3.4 Molccular identification
    2.4 Results and discussion
        2.4.1 Results
            2.4.1.1 Morphogical characteristics of isolate KML
            2.4.1.2 Physiological and biochemical characteristics
            2.4.1.3 Molecular identification
        2.4.2 Discussion
    2.5 Conclusions
    References
Chapter3 Biodegradation of diesel oil by isolate KML
    3.1 Introduction
    3.2 Materials
        3.2.1 Microorganisms source
        3.2.2 Media and reagents
            3.2.2.1 Media
            3.2.2.2 Reagents
        3.2.3 Chemicals
        3.2.4 Equipments
    3.3 Methods
        3.3.1 Enrichment method
        3.3.2 Biodegradation studies
            3.3.2.1 Inoculum preparation
            3.3.2.2 Standard curve of diesel
            3.3.2.3 Time course of diesel oil degradation by isolate KML
        3.3.3 Effects of various factors on the biodegradation
            3.3.3.1 Effect of temperature
            3.3.3.2 Effect of pH on diesel oil degradation
            3.3.3.3 Effect of different nitrogen sources on diesel degradation
            3.3.3.4 Effect of different yeast concentration
            3.3.3.5 Effect of different rhamnolipid concentration
            3.3.3.6 Effect of different inoculum concentration
            3.3.3.7 Effect of different diesel oil concentration
    3.4 Results and discussion
        3.4.1 Results
            3.4.1.1 Standard curve of diesel oil concentration
            3.4.1.2 Biodegradation essay of isolate KML
            3.4.1.3 Effect of pH
            3.4.1.4 Effect of temperature on diesel degradaiton by isolate KML
            3.4.1.5. Effect of different nitrogen sources
            3.4.1.6 Effect of yeast extract concentration
            3.4.1.7 Effect of rhamnolipid concentration
            3.4.1.8. Effect of inoculum concentration
            3.4.1.9 Effect of diesel oil concentration on diesel degradation by isolate KML
        3.4.2 Discussion
    3.5 Conclusions
    References
Chapter 4 GC-MS analysis of diesel oil components
    4.1 Introduction
    4.2 Materials
        4.2.1 Medium and chemicals
        4.2.2 Equipments
    4.3 Methods
    4.4. Results and discussion
    4.5 Conclusions
    References
Chapter 5 Conclusion and future work
    5.1 Conclusions
    5.2 Future work
Acknowledgements
Publications



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