本文選題：氫氣　切入點(diǎn)：產(chǎn)氣腸桿菌　出處：《浙江大學(xué)》2017年碩士論文　論文類型：學(xué)位論文

【摘要】：由于化石能源日益減少,氫能作為一種可再生清潔能源吸引了越來越多的關(guān)注。微生物發(fā)酵制取生物氫氣以其環(huán)境友好、低能耗特點(diǎn),因而具有很強(qiáng)應(yīng)用前景。產(chǎn)氣腸桿菌(Enterobacter aerogenes)兼性厭氧,生長(zhǎng)速度快,產(chǎn)氫速率高,有望應(yīng)用于工業(yè)生產(chǎn)中。本文研究了核輻射誘變產(chǎn)氣腸桿菌利用色圈法篩選優(yōu)勢(shì)突變體,通過增強(qiáng)氫酶活性及優(yōu)化代謝途徑提高其產(chǎn)氫能力;將纖維素生物質(zhì)蒸汽稀酸預(yù)處理高效水解后,利用產(chǎn)氣腸桿菌突變體發(fā)酵提高產(chǎn)氫量。首次利用鈷60-γ射線對(duì)產(chǎn)氣腸桿菌進(jìn)行核輻照誘變,并利用酸性副產(chǎn)物色圈法篩選高效的產(chǎn)氫突變株。色圈大小代表了細(xì)菌代謝產(chǎn)酸多少,色圈越大表明代謝產(chǎn)酸量越多,氫氣產(chǎn)量極有可能提高。篩選獲得具有較大色圈的突變株E.aerogenes ZJU1,其氫酶活性157.4 mL H2/(g DW·h)明顯高于野生菌株的氫酶活性89.8mLH2/(gDW·h)。突變株的糖酵解和丙酮酸代謝增強(qiáng),甲酸氫氣裂解酶、氫酶活性提高,促進(jìn)了 FHL途徑和NADH途徑產(chǎn)氫。突變株的氫氣產(chǎn)量為301 mLH2/g葡萄糖,比野生株產(chǎn)氫量(166mLH2/g葡萄糖)提高了 81.8%。'突變株的產(chǎn)氫速率峰值為27.2 mLH2/(L·h),比野生菌株的產(chǎn)氫速率峰值(19.3 mL H2/(L·h))提高了 40.9%。突變株發(fā)酵產(chǎn)氫過程中的液相副產(chǎn)物乙酸和丁酸產(chǎn)量高于野生株,而乙醇產(chǎn)量降低,這與突變株的產(chǎn)氫能力提高是一致的。通過迭代培養(yǎng)驗(yàn)證了突變株E.aerogenes ZJU1的產(chǎn)氫能力具有遺傳穩(wěn)定性。突變株E.aerogenes ZJU1利用預(yù)處理高效水解的水花生促進(jìn)發(fā)酵產(chǎn)氫。微觀測(cè)試表明:蒸汽稀酸預(yù)處理對(duì)水花生纖維素結(jié)構(gòu)造成了嚴(yán)重破壞,大量碎片降解并且出現(xiàn)許多裂痕;結(jié)晶纖維素減少,非結(jié)晶纖維素增加,水花生的結(jié)晶度指數(shù)由17.6降低至10.8。水花生的還原糖產(chǎn)量在最佳預(yù)處理工況下(硫酸濃度1%,蒸汽溫度135℃,加熱時(shí)間15min)達(dá)到0.354g/g生物質(zhì),酶水解后達(dá)到0.575 g/g生物質(zhì)。產(chǎn)氣腸桿菌突變株E.aerogenes ZJU1利用高效水解后的水花生發(fā)酵產(chǎn)氫量達(dá)到62.2mLH2/g-TVS,比野生菌的發(fā)酵產(chǎn)氫量(47.2mLH2/g-TVS)提高了 31.8%。通過優(yōu)化發(fā)酵菌液量得到最大單位產(chǎn)氫速率由1.42mLH2/g-TVS/h提高至4.64mLH2/g-TVS/h,同時(shí)氫氣產(chǎn)量提高了 42.8%達(dá)到89.8mLH2/g-TVS。
[Abstract]:Because of the decreasing of fossil energy, hydrogen energy as a kind of renewable clean energy has attracted more and more attention. Microbial fermentation to produce biological hydrogen is environmentally friendly and low energy consumption. Therefore, Enterobacter aerogenes (Enterobacter aerogenes) facultative anaerobic, rapid growth rate and high hydrogen production rate are expected to be used in industrial production. The hydrogen production ability was improved by enhancing the activity of hydrogen enzyme and optimizing the metabolic pathway. The fermentation of Enterobacter aerogenes mutant was used to increase hydrogen production. Cobalt 60- 緯 -ray was used to mutate Enterobacter aerogenes by nuclear irradiation for the first time. The size of color circle represents the amount of acid produced by bacteria metabolism, and the larger the color circle is, the more the amount of metabolic acid production is. The hydrogen production of E. aerogenes ZJU 1 with large color circle was significantly higher than that of wild strain E. aerogenes ZJU 1. The glycolysis and pyruvate metabolism of the mutant strain were enhanced, and the hydrogen formic acid lyase activity of the mutant strain was significantly higher than that of wild strain E. aerogenes ZJU 1, and the hydrogen formic acid lyase of E. aerogenes ZJU 1 was significantly higher than that of wild strain E. aerogenes ZJU 1. The activity of hydrogenase increased, which promoted hydrogen production by FHL pathway and NADH pathway. The hydrogen production of mutant was 301 mLH2/g glucose. The hydrogen production rate of mutant strain was 27.2 mLH2/(L 路HG, which was higher than that of wild strain (19.3 mLH2/(L 路HG glucose). The liquid phase by-products acetic acid and butyric acid in hydrogen production of mutant strain were higher than that of wild strain (19.3 mLH2/(L 路HG glucose), and the hydrogen production rate of mutant strain was higher than that of wild strain strain (166mLH2 / g glucose). The liquid phase by-products acetic acid and butin in the process of hydrogen production of mutant strain were increased by acetic acid and butyric acid. The acid yield was higher than that of wild plants. And ethanol production is down, The hydrogen production ability of the mutant E. aerogenes ZJU1 was proved to be of genetic stability by iterative culture. The mutant E.aerogenes ZJU1 was used to promote the production of hydrogen by pretreated and highly hydrolyzed peanut. The results showed that the cellulose structure of peanut was seriously damaged by steam dilute acid pretreatment. Large amounts of debris degrade and many cracks occur; crystalline cellulose decreases, amorphous cellulose increases, The crystallinity index of water peanut was reduced from 17.6 to 10.8. Under the optimum pretreatment condition (sulfuric acid concentration 1, steam temperature 135 鈩，

本文編號(hào)：1598143