本文選題：鄰苯二甲酸二丁酯　切入點(diǎn)：降解動(dòng)力學(xué)　出處：《東北農(nóng)業(yè)大學(xué)》2015年碩士論文

【摘要】：DBP(鄰苯二甲二丁酯)是一種PAEs(鄰苯二甲酸酯)化合物,作為一種塑化劑被廣泛使用在生產(chǎn)生活中。目前,DBP在環(huán)境中普遍存在,對(duì)人體具有“三致”毒性。環(huán)境中自發(fā)光降解、水降解及微生物降解不能有效的分解DBP,因此篩選高效降解DBP菌株才是有效降低PAEs濃度的途徑。本研究以DBP做為唯一的碳源從哈爾濱市某荒廢污染土壤中分離出一種具有高效DBP降解能力的菌株DNB-S1,采用形態(tài)學(xué)、生理生化指標(biāo)、16Sr DNA鑒定菌種,并對(duì)其生長(zhǎng)特性、降解特性進(jìn)行了研究。對(duì)DNB-S1的降解酶進(jìn)行定位,對(duì)其最適條件進(jìn)行了探究,采用海藻酸鈉固定該酶,并用室內(nèi)盆栽試驗(yàn)初步驗(yàn)證了固定化酶的降解效果。(1)分離獲得一株DBP高效降解菌,經(jīng)鑒定為假單胞菌(Pseudomonas sp.),命名為DNB-S1,該菌株在透射電鏡下呈桿狀,長(zhǎng)1721nm寬709nm,以極生鞭毛運(yùn)動(dòng),無(wú)細(xì)胞核。菌落為白色、邊緣為鋸齒狀、中心凸起、圓形、無(wú)芽抱。革蘭氏染色呈陰性,并且為嚴(yán)格耗氧菌,能以DBP為唯一碳源生長(zhǎng)。(2)DNB-S1菌株的最適生長(zhǎng)條件為,DBP濃度500mg/L,溫度35℃,p H為7.0,接菌量為3%,搖床轉(zhuǎn)速設(shè)置為125r/min,高濃度的DBP(2000mg/L)含量會(huì)對(duì)DNB-S1的生長(zhǎng)具有一定抑制作用。在該條件下培養(yǎng)菌株48h,測(cè)定發(fā)現(xiàn),DNB-S1對(duì)500mg/L DBP的降解率為90%,得到DNB-S1一級(jí)動(dòng)力學(xué)方程ln c?6.444?0.032t(R2=0.9837),降解半衰期為20.9小時(shí)。(3)DNB-S1的降解酶為胞內(nèi)酶。酶促反應(yīng)最適條件為:35℃,p H=7.0,該條件下反應(yīng)24h后,可將500mg/L的DBP降解85.6%。(4)選用海藻酸鈉為固定化材料對(duì)DNB-S1胞內(nèi)酶進(jìn)行固定化處理,最佳固定條件為:固定化體系(18ml)中粗酶液最佳添加量為900ug,海藻酸鈉的質(zhì)量分?jǐn)?shù)為1.0%,包埋比1:2,Ca Cl2溶液質(zhì)量分?jǐn)?shù)為2.0%。在24h內(nèi)固定化酶小球可以將500mg/L的DBP降解到98.5mg/L,降解率可以達(dá)到80.3%。(5)分別設(shè)置空白處理、游離酶處理、固定化酶處理3個(gè)不同的修復(fù)組,進(jìn)行室內(nèi)盆栽模擬修復(fù)試驗(yàn),初始土壤DBP含量為25mg/kg,在第0、7、14、21、28天取樣檢測(cè)剩余DBP含量。同空白處理比較,添加降解酶之后,DBP的含量明顯降低,經(jīng)過(guò)28天的處理之后,游離酶降解率為63.2%,效果顯著。固定化酶的修復(fù)效果更加出色,28天的DBP降解率為91.01%,DBP含量降低至2.2mg/kg,遠(yuǎn)遠(yuǎn)低于美國(guó)土壤污染的治理標(biāo)準(zhǔn)8.1mg/kg,到達(dá)修復(fù)目的。
[Abstract]:DBP (phthalic dibutyl ester) is a kind of PAes (phthalate) compound, which is widely used in production and life as a plasticizer. At present, DBP is ubiquitous in the environment and has "tritoxic" toxicity to human body. Water degradation and microbial degradation can not effectively decompose DBP, so screening high efficient degradation of DBP strains is the effective way to reduce the concentration of PAEs. In this study, DBP is the only carbon source isolated from a waste polluted soil in Harbin. The strain DNB-S1, which has the ability to degrade DBP efficiently, was characterized by morphology. The physiological and biochemical index, 16Sr DNA, was used to identify the strain, and its growth and degradation characteristics were studied. The optimum conditions of DNB-S1 degradation enzyme were studied, and the enzyme was immobilized by sodium alginate. A strain of Pseudomonas sp. Sp., named DNB-S1, was isolated and identified as Pseudomonas sp. (1) the strain was identified as Pseudomonas sp. sp. and named DNB-S1. The strain was rod shaped under transmission electron microscope with a long 1721nm width of 709nmand moved to polar flagella. Without nucleus. Colony is white, margin is serrated, central protuberance, round, no bud clasping. Gram staining negative, and strictly oxygen consuming bacteria, The optimum growth conditions of DNB-S1 strain can be grown with DBP as the sole carbon source: the concentration of DNB-S1 is 500 mg / L, the temperature is 35 鈩，

本文編號(hào)：1669362