本文選題：揮發(fā)性脂肪酸 + 餐廚垃圾��； 參考：《浙江工商大學》2017年碩士論文

【摘要】：揮發(fā)性脂肪酸(VFAs),作為合成許多生物能源(氫氣和甲烷等)的前體,在工業(yè)上有廣泛的應用。目前,VFAs的合成主要通過化學方法,但該法耗能巨大;而利用生物法(厭氧發(fā)酵技術)合成VFAs具有一定的優(yōu)越性。厭氧發(fā)酵是一種基于生物質(zhì)生成高附加值產(chǎn)物的可再生過程。餐廚垃圾中有機物含量較高,適宜通過厭氧發(fā)酵技術生產(chǎn)VFAs。利用餐廚垃圾厭氧發(fā)酵生產(chǎn)揮發(fā)性有機酸的研究也逐漸興起,但該過程仍存在較多的限制性因素�；诓蛷N垃圾厭氧發(fā)酵產(chǎn)酸過程中存在的預處理方法的非經(jīng)濟性、厭氧條件的難控制性以及垃圾組分的低轉化率等問題展開本文的研究。首先,評估了一種經(jīng)濟環(huán)保的預發(fā)酵處理方式對餐廚垃圾產(chǎn)酸的作用;并將其與水熱預處理聯(lián)合,觀察它們對產(chǎn)酸效果的影響,初步探究產(chǎn)酸機理。其次,探究氧化還原電位(ORP)對餐廚垃圾水解產(chǎn)酸的影響規(guī)律,結合微生物群落結構分析產(chǎn)酸機理,明確最佳的發(fā)酵產(chǎn)酸條件。最后,研究餐廚垃圾中不同蛋白質(zhì)組分發(fā)酵產(chǎn)酸的特性,分析剩余蛋白的組成,明確其轉化效率低的限制性因素。本文主要獲得以下結論:(1)預發(fā)酵和預發(fā)酵+水熱預處理可以有效地促進有機物的溶出和水解。餐廚垃圾預發(fā)酵處理形成的低pH環(huán)境有利于多聚糖的糖化,從而促進碳水化合物的水解。預發(fā)酵+水熱處理則更有利于一些復雜基質(zhì)(纖維素和蛋白質(zhì)等)的溶出。預處理后的餐廚垃圾在厭氧發(fā)酵初期產(chǎn)酸速率明顯增加。但是由于餐廚垃圾本身的高纖維素和高油脂含量,后期總產(chǎn)酸量受到抑制。此外,不同預處理的餐廚垃圾發(fā)酵產(chǎn)酸的途徑存在差異:預發(fā)酵處理的餐廚垃圾先轉化為乳酸,而后乳酸再轉化為VFAs;,預發(fā)酵+水熱處理后的垃圾則直接轉化為VFAs。經(jīng)濟性評估表明,預發(fā)酵+水熱處理是一種高產(chǎn)酸、低能耗的預處理方法(尤其對低油脂和低纖維素含量的餐廚垃圾而言)。(2)在pH6的產(chǎn)酸體系中,厭氧環(huán)境(ORP-200～-300 mV)并不利于產(chǎn)酸,而最適合餐廚垃圾發(fā)酵產(chǎn)酸的ORP范圍是-100～-200 mV。在保持最佳ORP水平時,接種厭氧微生物有利于促進有機質(zhì)(尤其是蛋白質(zhì))的降解;且該體系中微生物多樣性更豐富,Firmicutes的相對豐度更大,產(chǎn)酸量(0.79g COD/g VS)更多。厭氧發(fā)酵反應器中2-溴乙烷磺酸鹽(BES)的添加可以提高產(chǎn)酸量,主要是因為其增加了反應體系中產(chǎn)酸菌的豐度。(3)相同有機物含量的雞蛋蛋白和豆腐的發(fā)酵產(chǎn)酸量和產(chǎn)酸組成明顯不同。水熱預處理對于雞蛋蛋白的生物轉化是不利的。豆腐產(chǎn)酸以乙酸為主(乙酸型發(fā)酵);而雞蛋蛋白所產(chǎn)的各種有機酸的比例相近(混合酸型發(fā)酵)。兩種蛋白質(zhì)的產(chǎn)酸途徑也有差異:豆腐產(chǎn)酸嚴格地按照Stickland反應進行,蛋白質(zhì)水解為氨基酸,氨基酸直接轉化為乙酸、丙酸、丁酸和戊酸;雞蛋蛋白產(chǎn)酸除了轉化為乙酸、丙酸、丁酸和戊酸之外,同時合成大量乳酸。不同反應器中產(chǎn)酸量的差異也歸因于其中微生物群落結構的差異。Sporanaerobacter和Aminobacterium分別是豆腐(21.0%)和雞蛋蛋白(10.9～19.9%)產(chǎn)酸體系中的優(yōu)勢微生物;而且在雞蛋蛋白產(chǎn)酸反應器中檢測到更多的乳酸菌(Leuconostoc,Lactobacillus)根據(jù)氮平衡分析可知,所有反應器中蛋白質(zhì)的轉化效率與其產(chǎn)酸效率具有一致性。發(fā)酵結束時,所有反應器中仍剩余部分可溶性蛋白(占總蛋白的30～40%)未降解。通過蛋白質(zhì)分離,結果表明水熱處理后的兩種蛋白產(chǎn)酸體系中,剩余可溶性蛋白中約50%以蛋白酶的形式存在。
[Abstract]:Volatile fatty acids (VFAs) are widely used in industry as precursors for the synthesis of many bioenergy sources (hydrogen and methane). At present, the synthesis of VFAs is mainly through chemical methods, but this method has great energy consumption, and the synthesis of VFAs by biological method (anaerobic fermentation technology) has some advantages. Anaerobic fermentation is a kind of biomass based production. The regenerative process of high added value products. The content of organic matter in food waste is high. The research on the production of volatile organic acids by anaerobic fermentation by anaerobic fermentation technology by anaerobic fermentation technology is also gradually rising, but there are still many restrictive factors in this process. Based on the pretreatment of anaerobic fermentation of kitchen waste in the process of acid production, VFAs. The non economy of treatment, the difficult control of anaerobic conditions and the low conversion rate of the garbage components are studied in this paper. First, the effect of a kind of economic and environmental pre fermentation on the acid production of kitchen waste is evaluated, and the effect of them on the effect of acid production is observed and the effect of them on the acid producing effect is observed and the acid production is preliminarily explored. Secondly, the effect of the oxidation reduction potential (ORP) on the hydrolytic acid production of kitchen waste was investigated, and the optimum fermentation acid producing condition was determined by analyzing the mechanism of acid production by microbial community structure. Finally, the characteristics of acid production by different protein components in food waste were studied, the composition of the residual protein was analyzed, and the limitation of the conversion efficiency was clear. The main conclusions are as follows: (1) pre fermentation and pre fermentation + hydrothermal pretreatment can effectively promote the dissolution and hydrolysis of organic compounds. The low pH environment formed by pre fermentation of kitchen waste is beneficial to the saccharification of polysaccharides, thus promoting the hydrolysis of carbohydrates. Dissolution of cellulose and protein. The rate of acid production of kitchen waste in the early stage of anaerobic fermentation increased significantly. However, the total acid content in the later period was inhibited because of the high cellulose and high oil content of the kitchen waste itself. In addition, the ways of producing acid by different pretreated kitchen waste fermentation were different: the pretreated kitchen kitchen waste The garbage was converted to lactic acid first and then the lactic acid was converted to VFAs, and the pre fermentation and hydrothermal treatment was directly converted to the VFAs. economic assessment. The prefermentation and hydrothermal treatment was a high-yield acid, low energy consumption pretreatment method (especially for low oil and low cellulose content). (2) in the acid producing system of pH6, anaerobic digestion was anaerobic. The environment (ORP-200 to -300 mV) is not favorable for acid production, and the ORP range that is most suitable for food waste fermentation is that -100 to -200 mV. can promote the degradation of organic matter (especially protein) when maintaining the optimum ORP level, and the microbial diversity is more abundant, the relative abundance of Firmicutes is greater, and the acid yield is 0. .79g COD/g VS) more. The addition of 2- bromine ethane sulfonate (BES) in anaerobic fermentation reactor can increase acid production, mainly because it increases the abundance of acid bacteria in the reaction system. (3) the acid content and acid composition of the egg protein of the same organic content and the fermented bean curd are distinctly different. The conversion is unfavorable. The acid of bean curd is mainly acetic acid (acetic acid fermentation); and the proportion of all kinds of organic acids produced by egg protein is similar (mixed acid fermentation). The acid producing ways of the two kinds of proteins are also different: the bean curd produces acid strictly according to the Stickland reaction, the protein is hydrolyzed to amino acid, the amino acid is directly converted into acetic acid, propionic acid, Butyric acid and valerate; egg protein acids are produced in addition to acetic acid, propionic acid, butyric acid and valerate, and a large amount of lactic acid is synthesized. The difference in acidity in the different reactors is also attributed to the differences in microbial community structure between.Sporanaerobacter and Aminobacterium in the acid producing system of tofu (21%) and egg protein (10.9 to 19.9%), respectively. Dominant microorganisms, and more lactic acid bacteria (Leuconostoc, Lactobacillus) detected in egg protein acid producing reactor (Leuconostoc, Lactobacillus), according to nitrogen balance analysis, the conversion efficiency of protein in all reactors is consistent with the efficiency of acid production. At the end of the fermentation, all the remaining soluble proteins in all reactors (30~4 of the total protein) 0%) undegraded. Through protein separation, the results showed that about 50% of the remaining soluble proteins were found in the form of protease in the two protein producing systems after hydrothermal treatment.
【學位授予單位】：浙江工商大學
【學位級別】：碩士
【學位授予年份】：2017
【分類號】：TQ921;X799

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本文編號：1943107