木薯淀粉废水培养复合微生物絮凝剂产生菌的条件优化

发布时间：2018-08-13 18:39

【摘要】：木薯淀粉废水属于食品工业中的高浓度有机废水,含有大量的粗蛋白和一定量的糖类,其含有的TN、TP可被用做微生物生长代谢所需能源物质,因此作为培养微生物絮凝剂产生菌的培养基质是较为理想的。本研究选用木薯淀粉厂的厌氧废水作为菌种分离原材料,筛选得到能够利用木薯淀粉废水生产高效絮凝剂的菌株；优化复合型微生物絮凝剂产生菌利用木薯淀粉废水产絮凝剂的营养条件和发酵工艺条件；并研究了复合微生物絮凝剂的絮凝性能、性质结构和絮凝机理。本研究获得的主要结论如下：(1)从厌氧废水中筛选出两株对木薯淀粉废水具有高絮凝活性的乳酸菌LB3.LB5,其复合菌体发酵液对淀粉废水的絮凝率可达到74.8%。经16SrDNA基因同源性分析鉴定,LB3为干酪乳杆菌(Lactobacillus casei)、LB5为植物乳杆菌(Lactobacillus plantarum)。(2)通过单因素实验研究木薯淀粉废水培养复合菌体产絮凝剂的最佳条件为：以原木薯淀粉废水作为培养基质,不添加磷源物质,补充碳源为葡萄糖,复合氮源以酵母膏和蛋白胨按1：2添加,其补加碳氮源添加总量为4.5%,碳氮比值为1.5,废水初始pH为5.5,菌株LB3、B5按总接种量5%配比1：4接种于灭菌废水培养基,在30 ℃ 150r/min条件下培养48 h,发酵液对淀粉废水和高岭土悬液的絮凝率均可达到85%以上。(3) 复合微生物絮凝剂的较佳助凝剂为CaCl2。按絮凝剂投药量20mL, 1% CaCl2投加4 mL于200 mL淀粉废水及高岭土悬液中,絮凝后静置30 min,其絮凝率分别可达到83.7%、91.7%。(4)复合絮凝剂MBF-LB35具有良好的热稳定性,其絮凝活性成分主要是以多糖类物质为主,含有极少量的蛋白质,质量分数分别为46.81%、5.88%,且复合菌体LB3、LB5细胞表面的絮凝活性物质也属于多糖类。复合絮凝剂MBF-LB35中含有大量的羧基和羟基,这些基团能促进絮凝剂在水中的溶解性,增强絮凝剂分子的伸展性,增加分子的有效长度,有利于吸附架桥作用。
[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，

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