甜高粱秸秆高温发酵联产氢气和挥发性脂肪酸

发布时间：2020-12-17 03:13

　　面对当今世界对可再生能源日益增长的需求,氢气作为一种环保、高能可再生能源,可保障未来的能源安全。木质纤维素生物质可转化并产生能源和化学品,替代化石燃料满足能源需求,同时减少二氧化碳的大气排放,是一类环境友好型的可再生资源。本论文主要关注甜高粱秸秆的厌氧生物发酵产氢气和挥发性脂肪酸。由于在微生物发酵过程中,甜高粱秸秆所含的纤维素和半纤维等结构性多糖难以被有效利用,如何提高结构性多糖的利用度和发酵产物的产量,成为本论文研究重点。共培养Clostridium thermocellum和Clostridium thermosaccharolyticum发酵甜高粱秸秆,当底物浓度为5g/L,接种C.thermocell.m培养24h之后,以1:1比例接种C.thermosaccharolyticum可以获得最大的氢气和挥发性脂肪酸产量,氢气产量为5.1 mmol/g-substrate,乙酸为1.27g/L,丁酸为1.05g/L。相比于单菌培养氢气、乙酸和丁酸的产量分别提高了55%、9%、10%。通过C.thermosaccharaolyticum两步发酵结合稀酸处理第一步发酵残渣的新工艺,进一... 

【文章来源】：中国科学院大学(中国科学院过程工程研究所)北京市

【文章页数】：129 页

【学位级别】：博士

【文章目录】：
Abstract
摘要
1. Introduction
    1.1 Bio-hydrogen and volatile fatty acid
        1.1.1 Bio-hydrogen
        1.1.2 Volatile fatty acid
        1.1.3 Biosynthetic pathways
        1.1.4 Process parameters for hydrogen and VFA fermentation
            1.1.4.1 Temperature
            1.1.4.2 pH
            1.1.4.3 Hydrogen partial pressure
    1.2 Lignocellulosic biomass for hydrogen and VFA production
        1.2.1 Substrates
        1.2.2 Pretreatment of substrates
            1.2.2.1 Physical pretreatments
            1.2.2.2 Chemical pretreatments
            1.2.2.3 Biological pretreatments
            1.2.2.4 Combined pretreatments
            1.2.2.5 Inhibitory compounds
    1.3 Sweet sorghum stalk
        1.3.1 Potential uses of sweet sorghum
            1.3.1.1 Food/feed
            1.3.1.2 Biofuel feedstock
            1.3.1.3 Sweet sorghum biorefinery
    1.4 Aims and objectives
2. Coproduction of hydrogen and VFA by thermophilic fermentation fromco-culture of C. thermocellum and C. thermosaccharolyticum
    2.1 Introduction
    2.2 Experimental methodology
        2.2.1 Materials and chemicals
        2.2.2 Microorganisms and culture condition
        2.2.3 Experimental design
        2.2.4 Analytical methods
    2.3 Results and discussion
        2.3.1 Effect of the inoculation ratio of C. thermosaccharolyticum to C.thermocellum on hydrogen and VFA production
        2.3.2 Effect of substrate concentration to optimize the maximum conversion forco-culture of C. thermosaccharolyticum to C. thermocellum on hydrogenand VFA
        2.3.3 Optimization of inoculation time gap between C. thermosaccharolyticumfollowed by C. thermocellum
        2.3.4 Hydrogen and VFA production from single-culture of C.thermosaccharolyticum and co-culture of C. thermocellum and C.thermosaccharolyticum
    2.4 Conclusions
3. Coproduction of hydrogen and VFA by two-step fermentation with dilute acidtreatment in between
    3.1 Introduction
    3.2 Experimental methodology
        3.2.1 Materials and chemicals
        3.2.2 Microorganism and culture conditions
st step fermentation">        3.2.3 1^st step fermentation
nd step fermentation">        3.2.4 Dilute acid treatment and 2^nd step fermentation
        3.2.5 Analytical methods
    3.3 Results and discussion
st step dark fermentation of sweet sorghum stalk by C.thermosaccharolyticum">        3.3.1 1^st step dark fermentation of sweet sorghum stalk by C.thermosaccharolyticum
st step fermentation">        3.3.2 Acid treatment on residual biomass after 1^st step fermentation
        3.3.3 Effect of acid concentration with different reaction temperature on residualbiomass for hydrogen, acetic acid and butyric acid production
        3.3.4 Total hydrogen and VFA production from one step fermentation and twostep fermentation with dilute acid treatment in between
    3.4 Conclusion
4. Coproduction of hydrogen and volatile fatty acid by two-step fermentationintegrated with alkali and enzyme treatment in between
    4.1 Introduction
    4.2 Experimental methodology
        4.2.1 Materials and chemicals
        4.2.2 Microorganism and culture conditions
st step fermentation">        4.2.3 1^st step fermentation
nd step fermentation">        4.2.4 Alkali treatment followed by enzyme hydrolysis and 2^nd step fermentation
        4.2.5 Analytical methods
    4.3 Results and discussion
st step dark fermentation by C.thermosaccharolyticum">        4.3.1 Fermentability of sweet sorghum stalk in 1^st step dark fermentation by C.thermosaccharolyticum
st step fermentation: effect ofNaOH loading and reaction temperature on composition of residualbiomass">        4.3.2 Alkali treatment on residual biomass after 1^st step fermentation: effect ofNaOH loading and reaction temperature on composition of residualbiomass
st step fermentation">        4.3.3 Effect of NaOH loading and reaction temperature on enzymatic digestibilityof residual substrate from 1^st step fermentation
        4.3.4 Effect of NaOH concentration with different reaction temperature onresidual biomass for hydrogen, acetic acid and butyric acid production
        4.3.5 Total hydrogen and VFA yields in one step and two step fermentation withNaOH followed by cellulase enzyme treatment in between
    4.4 Comparison of hydrogen and organic acid production performance for differenttreatment methods
    4.5 Techno-economic comparison of different anaerobic dark fermentation processes
    4.6 Conclusion
5. Conclusions and prospective
    5.1 Conclusion
    5.2 Novelty
    5.3 Prospective
List of abbreviations
References
Acknowledgements
Curriculum vitae



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