一株低温高效植物油降解菌的驯化筛选及固定化研究

为了解决因低温而导致的废水中油脂难以处理的问题,从冬季重庆大学餐厅排污管道的底泥中分离出1株可低温降解植物油的菌株DJ-1。将此菌株多次驯化培养后,在5℃条件下利用其对含20g/L菜籽油复筛培养基的模拟含油废水进行处理。经过3 d处理,可去除废水中70.63%的植物油。经16S rDNA测序分析,该菌株为假单胞菌的一个未定种属(相似度为99%)。使用泥炭和木屑作为固定化载体,按照m(泥炭)∶m(木屑)∶m(菌液)=1∶4∶20的比例将扩培后的DJ-1菌剂制作成细菌固定化菌粉。在5℃条件下利用菌粉对含20 g/L菜籽油复筛培养基的模拟含油废水进行处理,菌粉投加量为0.15 g/L。经过3 d处理,废水中植物油的降解率达到77.34%,5 d后达到85.22%。

Acclimation, screening and immobilization of a high-efficient and low-temperature plant oil-degrading strain

The study aims at solving the problem that it is difficult to dissolve oil in sewage in the low temperature.For our research purpose,we began to attack the problem with the strain collection and separation from the sludge in winter days.Then we have done careful analysis and investigation of the physiological and biochemical characteristics through experiments by means of some advanced molecular biotechnology.And later,we have managed to the strain immobilized into a strain powder and determine the optimal time and effect of the bacterium through the strain powder recovery.And,finally,we have implemented the strain powder-adding experiment and gained the optimized dosing quantity of the strain powder and the ideal treating time.According to the above method,the DJ-1 strain proves to be capable of effectively degrading the plant oil and split from the pipeline sludge originated from a Chongqing University dining hall in winter.When the strain was used for treating simulated sewage containing 20 g/L rapeseed oil,we were engaged in the study of a secondary screening medium under 5 ℃ in our case study.The plant oil in the simulated sewage was 70.63% degraded by the inocula after 3 days treatment.In so doing,the DJ1 strain has proved to be an undecided species of Pseudomonas sp.through sequencing analysis(the similarity degree is as high as 99%).The latter experiment has been conducted with the adopted peat and sawdust as immobilized bacteria carrier(mass ratio of peat/sawdust/bacteria liquid=1:4:20),with the DJ1 strain made to be the immobilized strain powder after the expanded culture.When the immobilized strain powder was used in treating the simulated sewage containing 0.20 g/L rapeseed oil and secondary screening medium at the temperature of 5 ℃ with 0.15 g/L dosing quantity bacterial powder.The conclusion of our study is: the degraded efficiency of 20 g/L rapeseed oil can be as high as to 77.34% within 3 days and 85.22% within 5 days.