【摘要】：木薯淀粉廢水屬于食品工業(yè)中的高濃度有機廢水,含有大量的粗蛋白和一定量的糖類,其含有的TN、TP可被用做微生物生長代謝所需能源物質(zhì),因此作為培養(yǎng)微生物絮凝劑產(chǎn)生菌的培養(yǎng)基質(zhì)是較為理想的。本研究選用木薯淀粉廠的厭氧廢水作為菌種分離原材料,篩選得到能夠利用木薯淀粉廢水生產(chǎn)高效絮凝劑的菌株；優(yōu)化復(fù)合型微生物絮凝劑產(chǎn)生菌利用木薯淀粉廢水產(chǎn)絮凝劑的營養(yǎng)條件和發(fā)酵工藝條件；并研究了復(fù)合微生物絮凝劑的絮凝性能、性質(zhì)結(jié)構(gòu)和絮凝機理。本研究獲得的主要結(jié)論如下：(1)從厭氧廢水中篩選出兩株對木薯淀粉廢水具有高絮凝活性的乳酸菌LB3.LB5,其復(fù)合菌體發(fā)酵液對淀粉廢水的絮凝率可達到74.8%。經(jīng)16SrDNA基因同源性分析鑒定,LB3為干酪乳桿菌(Lactobacillus casei)、LB5為植物乳桿菌(Lactobacillus plantarum)。(2)通過單因素實驗研究木薯淀粉廢水培養(yǎng)復(fù)合菌體產(chǎn)絮凝劑的最佳條件為：以原木薯淀粉廢水作為培養(yǎng)基質(zhì),不添加磷源物質(zhì),補充碳源為葡萄糖,復(fù)合氮源以酵母膏和蛋白胨按1：2添加,其補加碳氮源添加總量為4.5%,碳氮比值為1.5,廢水初始pH為5.5,菌株LB3、B5按總接種量5%配比1：4接種于滅菌廢水培養(yǎng)基,在30 ℃ 150r/min條件下培養(yǎng)48 h,發(fā)酵液對淀粉廢水和高嶺土懸液的絮凝率均可達到85%以上。(3) 復(fù)合微生物絮凝劑的較佳助凝劑為CaCl2。按絮凝劑投藥量20mL, 1% CaCl2投加4 mL于200 mL淀粉廢水及高嶺土懸液中,絮凝后靜置30 min,其絮凝率分別可達到83.7%、91.7%。(4)復(fù)合絮凝劑MBF-LB35具有良好的熱穩(wěn)定性,其絮凝活性成分主要是以多糖類物質(zhì)為主,含有極少量的蛋白質(zhì),質(zhì)量分數(shù)分別為46.81%、5.88%,且復(fù)合菌體LB3、LB5細胞表面的絮凝活性物質(zhì)也屬于多糖類。復(fù)合絮凝劑MBF-LB35中含有大量的羧基和羥基,這些基團能促進絮凝劑在水中的溶解性,增強絮凝劑分子的伸展性,增加分子的有效長度,有利于吸附架橋作用。
[Abstract]:Cassava starch wastewater is a kind of high concentration organic wastewater in food industry. It contains a lot of crude protein and a certain amount of sugar. Therefore, as the culture substrate of microbial flocculant-producing bacteria, it is more ideal. In this study, the anaerobic wastewater from cassava starch plant was selected as the raw material for the isolation of bacteria, and the strains which could produce high efficiency flocculant from cassava starch wastewater were screened. The nutrient and fermentation conditions of cassava starch waste aquatic flocculant were optimized, and the flocculation properties, properties and flocculation mechanism of compound microbial flocculant were studied. The main conclusions of this study are as follows: (1) two lactic acid bacteria LB3.LB5 with high flocculation activity were screened from anaerobic wastewater. The flocculation rate of the compound fermentation broth on starch wastewater was 74.8%. By homology analysis of 16SrDNA gene, LB3 was identified as Lactobacillus casei (Lactobacillus casei) and LB5 as Lactobacillus plantarum (Lactobacillus plantarum). (2. The optimal conditions for the production of flocculant from cassava starch wastewater culture were as follows: the original cassava starch wastewater was used as the culture substrate. No phosphorus source was added, carbon source was glucose, compound nitrogen source was added with yeast extract and peptone at 1:2, The total amount of adding carbon and nitrogen source was 4.5, the ratio of carbon to nitrogen was 1.5, the initial pH of wastewater was 5.5, and the strain LB3OB5 was inoculated in the sterilizing wastewater medium at 1:4 according to the total inoculation amount of 5%. At 30 鈩，

本文編號：2181842