餐厨垃圾糖化液发酵制丁醇及糖化残渣堆肥化研究

发布时间：2018-04-29 07:13

本文选题：餐厨垃圾 + 丁醇发酵　；参考：《北京科技大学》2016年博士论文

【摘要】：本文针对餐厨垃圾制丁醇和堆肥的各自特点,将餐厨垃圾糖化后离心分离,上层液体(糖化液)用于制丁醇,下层残渣(糖化残渣)用于堆肥。这种组合方式既拓宽丁醇生产的原料来源,又解决了餐厨垃圾复杂成分中无法被丁醇菌利用的残渣资源化问题。餐厨垃圾热力学分析表明,与传统原料相比餐厨垃圾丁醇发酵省去糊化和液化等步骤,直接进行糖化,既省去蒸煮设备又节能、简化操作步骤,降低生产成本。同时优选出C. beijerinckii NCIMB 8052丁醇生产菌,以餐厨垃圾糖化液为底物,在未添加任何营养物质(即非调控状态),丁醇、总溶剂浓度及丁醇生产速率分别为5.95 g/L、8.23 g/L,0.139 g/L/h。但非调控状态下糖化液丁醇发酵出现“酸崩”现象,导致发酵启动较慢,相转型延滞和产物浓度较低等问题,通过添加0.3% (w/v) CaCO3可提高糖化液pH缓冲能力,解除“酸崩”抑制；进一步向糖化液添加5g/L酵母浸粉以刺激底物还原糖转化,丁醇、总溶剂及丁醇生产速率分别为11.7 g/L、16.7 g/L及0.308 g/L/h,与非调控状态相比分别提高96.6%、102.9%和121.6%。动力学模型表明促进目标产物生产,提高细胞生物量是关键措施所在,为此建立了高细胞密度批次发酵模式和高细胞密度循环连续发酵模式,前者的丁醇、总溶剂及丁醇生产速率分别为13.2 g/L、19.0g/L和0.746 g/L/h;后者的平均细胞生物量增殖为21.2 g/L,且丁醇生产速率高达1.37 g/L/h,分别是前者的1.94和1.84倍。因此,所建立的高细胞密度循环连续发酵模式是高效的。为使餐厨垃圾最大限度地资源化利用,对糖化残渣进行好氧堆肥并研究其AOB群落变化。结果表明,AOB群落结构随着物料温度升高发生明显变化,其中Nitrosomonas-like和Nitrosospira-like种属大量广泛存在于各个时期,Nitrosomonas europaea/eutropha是高温期优势菌属,它耐受性较强,在氨氮氧化过程中发挥着重要作用。冗余分析和方差分离的结果表明,NO3--N和pH值对AOB群落结构演替有显著影响(p＜0.05);NO3-N单独解释27.3%(p=0.012)AOB种群结构,pH值解释27.1% (p=0.024) AOB种群结构；这些参数对餐厨垃圾好氧堆肥过程中氨氧化细菌活性的调控具有重要意义。综上所述,餐厨垃圾糖化液发酵制丁醇和糖化残渣堆肥化的组合工艺是可行的,为餐厨垃圾能源化与资源化探索了一条新的途径。
[Abstract]:In this paper, according to the characteristics of butyl alcohol production and compost from kitchen waste, the waste is separated by centrifugation after saccharification, the upper liquid (saccharification liquid) is used to make butanol, and the lower layer residue (saccharification residue) is used in compost. This combination method not only broadens the raw material source of butanol production, but also solves the problem of recycling the residue which cannot be used by butanol bacteria in the complex ingredients of kitchen waste. The thermodynamics analysis of kitchen waste showed that compared with the traditional raw materials, butanol fermentation of kitchen waste saved gelatinization and liquefaction, and saccharified directly, which not only saved cooking equipment but also saved energy, simplified operation steps and reduced production cost. At the same time, C. beijerinckii NCIMB 8052 butanol producing bacteria were selected, and the saccharification solution of kitchen waste was used as substrate. The concentration of total solvent, the concentration of total solvent and the production rate of butanol were 5.95 g / L ~ (8.23) g / L ~ (0.139) g / L ~ (-1) 路h ~ (-1) without adding any nutrients (i.e., non-regulated state, butanol, total solvent concentration and the production rate of butanol). However, the phenomenon of "acid avalanche" appeared in the fermentation of saccharification liquid butanol under the condition of non-regulation, which led to the slow start of fermentation, the delay of phase transition and the low concentration of product. The pH buffer capacity of saccharification solution could be improved and the inhibition of "acid avalanche" could be relieved by adding 0.3% w / v) CaCO3. 5g/L yeast extract was added to the saccharification solution to stimulate the substrates to reduce sugar conversion, the production rate of butanol, total solvent and butanol was 11.7g / L 16.7 g / L and 0.308 g / L / h, respectively, which increased 96.6g / 102.9% and 121.6%, respectively, compared with the non-regulated state. The kinetic model showed that promoting the production of target products and increasing cell biomass were the key measures. Therefore, a batch fermentation model with high cell density and a continuous fermentation model with high cell density were established. The production rate of total solvent and butanol were 13.2g / L 19.0g / L and 0.746 g / L / h, respectively. The average cell biomass of the latter was 21.2 g / L, and the production rate of butanol was 1.37 g / L / h, which was 1.94 and 1.84 times higher than that of the former, respectively. Therefore, the established high cell density cycle continuous fermentation model is efficient. In order to maximize the utilization of kitchen waste, aerobic composting of saccharified residue was carried out and its AOB community change was studied. The results showed that the community structure of Nitrosomonas-like and Nitrosospira-like changed obviously with the increase of material temperature. The species of Nitrosomonas-like and Nitrosospira-like were the dominant genus of Nitrosomonas europaea/eutropha in high temperature stage, which had strong tolerance and played an important role in the process of ammonia nitrogen oxidation. The results of redundancy analysis and variance separation showed that no _ 3 N and pH value had a significant effect on the succession of AOB community structure. P < 0.05 no _ 3-N could explain the population structure of 27.3%(p=0.012)AOB alone and the pH value could explain 27.1% AOB population structure. These parameters play an important role in controlling the activity of ammonia-oxidizing bacteria in aerobic composting of kitchen waste. To sum up, it is feasible to produce butanol by fermentation of saccharification solution of kitchen waste and compost of saccharified residue, which provides a new way for energy conversion and resource utilization of kitchen waste.
【学位授予单位】：北京科技大学
【学位级别】：博士
【学位授予年份】：2016
【分类号】：X799.3;S141.4

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