紫外诱变选育鼠李糖脂高产菌并去除污泥中重金属的研究

发布时间：2018-02-02 03:25

  本文关键词： 鼠李糖脂 铜绿假单胞菌 诱变育种 条件优化 重金属 去除　出处：《广西大学》2015年硕士论文　论文类型：学位论文

【摘要】：鼠李糖脂是一种糖脂类的具有生物属性的表面功能之活性剂,其表面活性之能力以及乳化的能力不同反响,并且具有彻底的生物降解性,环境之友好程度表现出色,所以在石油工业、生物修复技术的应用行业、农业以及食药等行业具有不一般的实用价值。通过微生物的发酵过程就可以获得鼠李糖脂,一般来来此发酵过程温和,且对设备基本无特殊要求；不仅如此,需要的原料来源非常之广泛、而且价格超低。鼠李糖脂的另一神奇功效在于它的重金属铬的完美去除性。社会的发展肯定会对既清洁又安全还高效的鼠李糖脂有不断提高的需求。为此,本课题重点研究了能够生产鼠李糖脂的突变株的选育、它的发酵条件的优化组合,以及其在去除城市污泥重金属的重要贡献进行了研究。研究之结果如下所述：(1)此实验中诱变剂选定的就是紫外线,对保藏程度很好的一株能够代谢出鼠李糖脂的铜绿假单胞菌(Pseudomonas aeruginosa)菌株B0作了初步的诱变处理,然后再经过初复筛,于是就有了一株相对高产量的突变株B2,它的鼠李糖脂产量基本上有4.22 g·L-1,比之前的菌株提高了足足45.02%。(2)采用单因素实验和正交试验大大提升B2这个优异菌株,而且重点是发现了通过摇瓶来达到发酵目的的培养基构成以及培养的客观环境,确定了B2菌株摇瓶发酵的最优培养基组成以及培养条件为：碳源甘油30g·L-1、氮源酵母膏为2 g·L-1、磷源KH2PO4 10g·L-1、Na2HPO44g·L-1、微量元素为5 mL·L-1、温度30℃、原始酸碱值即7.0,发酵过程持续120小时。在最优的培养基基液及培养环境下,菌株B2出产量拨高到了6.03g·L-1,较出发菌株B0产量提高了近107.22%。(3)利用出发菌株B0和正突变优势菌株B2所产生物表面活性剂鼠李糖脂对城市污水处理厂污泥中的重金属进行去除研究发现,出发菌株B0正突变优势菌株B2所产生阴离子型生物表面活性剂鼠李糖脂污泥中的Cu、Zn能够有效地去除,减少了污泥中Cu、Zn的含量,降低了重金属对环境的威胁,并且随着鼠李糖脂浓度、pH值以及振荡时间的增加,污泥中重金属的解析率也随之增高。结果表明,污泥中Cu和Zn的去除效果与鼠李糖脂质量浓度、溶液pH值以及振荡提取时间有重要相关性。
[Abstract]:Rhamnolipid is a kind of glycolipid surfactant with biological properties. Its surface activity and emulsification ability are different, and they are completely biodegradable. The environmental friendliness is excellent, so in the petroleum industry, bioremediation technology application industry. Agriculture and medicine and other industries have special practical value. Through microbial fermentation process you can get rhamnolipid, generally come to this fermentation process is mild, and there is no special requirements for equipment; Not only that, the sources of raw materials needed are very wide. And the price is extremely low. Another magical effect of rhamnolipid is its perfect removal of heavy metal chromium. The development of society will definitely have an increasing demand for rhamnolipid, which is both clean, safe and efficient. For this reason. This paper focuses on the breeding of mutants capable of producing rhamnolipid and the optimization of its fermentation conditions. And its important contribution to the removal of heavy metals from municipal sludge. The results of the study are as follows: 1) in this experiment, the mutagens were selected as ultraviolet rays. Pseudomonas aeruginosa strain B0, a strain of Pseudomonas aeruginosa, which can metabolize rhamnolipid, was treated by mutagenesis. Then after the initial screening, there was a relatively high yield mutant B2, which basically produced 4.22 g 路L -1 rhamnolipid. Compared with the previous strain, the strain increased by 45.02%.) the single factor experiment and orthogonal test were used to improve the B 2 strain greatly. And the key point is to find out the composition of culture medium and the objective environment of culture by shaking flask to achieve the purpose of fermentation. The optimum medium composition and culture conditions of B2 strain were determined as follows: glycerol 30 g 路L -1, yeast extract 2 g 路L -1, KH2PO4 10 g 路L -1. Na2HPO44g 路L -1, trace element 5 mL 路L -1, temperature 30 鈩，

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