嗜热地衣芽孢杆菌特性的研究、改良及初步应用研究

发布时间：2018-04-24 21:21

  本文选题：嗜热地衣芽孢杆菌 + 黄原胶降解　； 参考：《中南林业科技大学》2017年硕士论文

【摘要】：黄原胶具有良好的流变性、乳化稳定性、悬浮性、兼容性及增粘性,在原油开采中常被用作驱替剂,以提高钻井、完井、调剖堵水及三次采油等过程中的采油率。在实际应用过程中发现,使用黄原胶后加大了后续处理工艺的难度,因此,有效地降解黄原胶是石油开采的重要工序。本研究以课题组前期鉴定的一株具有降解黄原胶能力的嗜热地衣芽孢杆菌HT-1为材料,对其进行紫外微波复合诱变,测定复合诱变菌株温度耐受性、pH耐受性以及对黄原胶的降解能力,并与原始菌株进行比较。最后,对复合诱变菌株的应用进行初步探索。本研究对后续黄原胶生物降解法以及黄原胶在石油工业的应用提供一定的参考依据。主要研究结果如下:原始菌株HT-1菌株的最适生长条件:温度50℃,pH 7.5,0.1%的黄原胶,1%的葡萄糖(碳源),1%的酵母粉(氮源);最适黄原胶降解条件:0.3%黄原胶作为唯一碳源和氮源,温度50℃,pH7.5。对原始菌株HT-1进行紫外诱变,选取一株较好的诱变菌株,命名为HT1UV-3,其对黄原胶的降粘率达到了 35.79%,较原始菌株提高了 14.42%。随后,对筛选得到的HT1UV-3突变株进行微波诱变,最终得到5株突变型菌株HT1UM3-1、HT1UM3-2、HT1UM3-3、HT1UM3-4、HT1UM3-5。温度耐受方面,5株突变菌株耐高温性能较原始菌株明显提高,其中HT1UM3-3菌株的最适生长温度趋于55℃;pH耐受方面,复合诱变菌株与原始菌株无明显差别;黄原胶降解方面,5株突变菌株的黄原胶降解能力较原始菌株均有提高,其中HT1UM3-5菌株的降粘率最高,达到42.02%,较原始菌株提高了 20.70%。在原油环境下,对原始菌株和复合诱变菌株的存活情况与黄原胶降解能力进行探索。结果显示,不同原油浓度下,原始菌株和复合诱变菌株对原油的耐受程度都不高,半数致死率均在0.5g/L;在0.5g/L原油浓度下,原始菌株和复合诱变菌株对黄原胶降解能力均较差,原始菌株降粘率趋近于0%,复合诱变菌株降粘率约7.5%。探究原始菌株和复合诱变菌株对瓜尔胶、田箐胶、卡拉胶三种胶的降解能力。结果表明,对瓜尔胶的降解上,所有菌株降解能力微弱,最大降粘率不超过4%;对田箐胶的降解上,HT1UM3-1、HT1UM3-2、HT1UM3-4、HT1UM3-5的降解能力略高于原始菌株,降粘率在5%-8%之间;对卡拉胶的降解上,复合诱变菌株的降解能力显著高于原始菌株,降粘率在10%-12%之间,较原始菌株提高了约60%。
[Abstract]:Xanthan gum has good rheology, emulsion stability, suspension, compatibility and viscosity. It is often used as a displacement agent in crude oil production to improve oil recovery rate in drilling, well completion, profile control, water shutoff and tertiary oil recovery. In the practical application, it is found that the use of xanthan gum increases the difficulty of subsequent treatment process. Therefore, the effective degradation of xanthan gum is an important process in petroleum exploitation. In this study, a strain of Bacillus licheniformis HT-1, which had the ability to degrade xanthan gum, was identified by our research group. The temperature tolerance and pH tolerance of the compound mutagenesis strain and its degradation ability to xanthan gum were determined and compared with the original strain. Finally, the application of compound mutagenesis strain was preliminarily explored. This study provides some references for the subsequent biodegradation of xanthan gum and the application of xanthan gum in petroleum industry. The main results were as follows: the optimum growth conditions of the original strain HT-1 were as follows: temperature 50 鈩，

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