混合光合产氢菌群的筛选及其产氢特性的研究

发布时间：2018-03-06 08:00

  本文选题：生物制氢　切入点：混合菌群　出处：《太原理工大学》2017年硕士论文　论文类型：学位论文

【摘要】：氢能作为理想的能源载体,具有清洁无污染、燃烧热值大、可储可输、来源广泛等优点。在众多生物制氢技术中,光合细菌光发酵制氢因低能耗、高效率,底物降解速率快,以及能将废水处理和能源生产有效地耦合起来,而备受关注。本文从湖底淤泥中采用生长培养基富集筛选得到混合菌群,命名为NG07。结合16S rDNA高通量测序对其进行鉴定分析,确定混合菌群NG07的优势菌种主要为红假单胞菌Rhodopseudomonas oryzae和类球红细菌Rhodobacter sphaeroides。以筛选的混合菌群NG07为研究对象,主要研究了培养过程中底物和环境因素对混合菌群的生长及产氢特性的影响。实验研究成果表明:(1)混合菌群NG07可利用多种糖类有机化合物产氢,其中葡萄糖为碳源时,产氢总量最大。随着葡萄糖浓度的增加,NG07的产氢总量逐渐增大,当葡萄糖浓度为100 mM时,产氢总量为4238.8±74 mL/L。但葡萄糖浓度对混合菌群的产氢速率、底物转化率、葡萄糖降解率的影响不同,当底物浓度为70 mM,NG07的最大产氢速率、底物转化率、和葡萄糖降解率都达到最大,分别为105.28±7.6 mL/h/L,底物转化率15.37%,和葡萄糖降解率99.40%。(2)在10 mM尿素的条件下,混合菌群NG07的产氢总量和最大产氢速率达到最大,分别为2872.2±38.31 mL/L和105.28±7.6 mL/h/L。(3)混合菌群NG07产氢的最佳Fe~(2+)浓度为5 mg/L。在5 mg/L的条件下,NG07的产氢总量和最大产氢速率达到最大,分别为3102.5±95.7 mL/L和114.9±9.1 mL/h/L,与对照相比分别增加了1.94倍和2.54倍。(4)搅拌能够提高光合细菌产氢的产氢速率和缩短反应停留时间,但对混合菌群的产氢总量影响比较小。在搅拌的条件下,其最大产氢速率为136.0±5.6mL/L/h,与对照组相比提高了29%。(5)NG07的最佳产氢温度是35℃。但温度为40℃时NG07仍具有良好的产氢性能,产氢总量为2638.5±52.7mL/L;而在45℃的条件下,NG07仍具有产氢活性,产氢总量为1050.0±28.7 mL/L,说明NG07具有很强的耐热性。(6)不同光照条件对混合菌群NG07的产氢总量和最大产氢速率的影响不同:产氢总量依次是12 h暗/12 h光循环连续光照≥连续黑暗12 h光/12 h暗循环条件;最大产氢速率依次是12 h暗/12 h光循环连续光照连续黑暗≥12 h光/12 h暗循环条件。(7)以聚乙烯醇作为固定化包埋材料时,混合菌群NG07的产氢活性明显优于琼脂和海藻酸钠。(8)Box-Behnken Design是以单因素试验为基础,以最大产氢速率为评价指标,对光合产氢工艺条件进行优化。得出最优条件为:Fe~(2+)浓度4.39 mg/L,温度33.36℃,葡萄糖浓度78.32 mM。在该条件下获得了199.3±6.5 mL/L/h的产氢速率,与最初条件相比提高了25.2%。由此可知,通过多因素实验优化得出的最佳产氢条件,不同于单因素实验的最佳条件,这就表明影响混合菌群产氢的各个因素之间存在交互作用。
[Abstract]:Hydrogen energy, as an ideal energy carrier, has the advantages of clean and pollution-free, high combustion calorific value, storage and transportation, wide source and so on. In many biological hydrogen production technologies, photofermenting hydrogen production by photosynthetic bacteria is characterized by low energy consumption, high efficiency, fast substrate degradation rate, and so on. In this paper, the mixed microflora was obtained by using growth medium enrichment and screening from the sludge of lake bottom, named NG07. combined with 16s rDNA high-throughput sequencing, it was identified and analyzed. The dominant species of mixed NG07 were Rhodopseudomonas oryzae and Rhodobacter sphaeroids. The effects of substrate and environmental factors on the growth and hydrogen production characteristics of mixed bacteria were studied in this paper. The experimental results showed that NG07 could produce hydrogen from various carbohydrate organic compounds, especially when glucose was a carbon source. With the increase of glucose concentration, the total hydrogen production of NG07 gradually increased. When glucose concentration was 100 mm, the total hydrogen production was 4238.8 卤74 mL / L. However, the hydrogen production rate and substrate conversion of mixed bacteria were increased by glucose concentration. The maximum hydrogen production rate, substrate conversion rate, and glucose degradation rate were all the highest when the substrate concentration was 70 mm / L NG07, which was 105.28 卤7.6 mL / h / L, respectively, and the substrate conversion rate was 15.37%, and the glucose degradation rate was 99.40.0.72) under the condition of 10 mm urea, respectively, when the substrate concentration was 70 mm / L NG07, the maximum hydrogen production rate, the substrate conversion rate and the glucose degradation rate were 105.28 卤7.6 mL / h / L, respectively. The total hydrogen production and the maximum hydrogen production rate of mixed NG07 were 2872.2 卤38.31 mL/L and 105.28 卤7.6 mL / L 路L 路L ~ (-3) respectively. The best Fe~(2 concentration of mixed NG07 was 5 mg / L 路L ~ (-1) 路L ~ (-1). The maximum hydrogen production and maximum hydrogen production rate were obtained at 5 mg/L. The hydrogen production rate and residence time of photosynthetic bacteria were increased by 1.94 times and 2.54 times, respectively (3102.5 卤95.7 mL/L and 114.9 卤9.1 mL / h / L, respectively, compared with the control). However, the effect of stirring on the total hydrogen production of mixed bacteria was relatively small. The maximum hydrogen production rate was 136.0 卤5.6 mL / L / h, and the optimum hydrogen production temperature was 35 鈩，

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