细菌-真菌复合菌群构建及石油烃降解条件优化

Construction of Bacterial-Fungal Composite Microbial Community and Optimization of Petroleum Hydrocarbon Degradation Conditions

为获得可高效降解石油烃的细菌-真菌复合菌群,首先通过比较单菌株的降解率,初步筛选出降解能力最高的2株细菌和2株真菌,进一步利用复配和正交等方法构建出具有最佳石油烃降解能力的复合菌群。通过16S rRNA和ITS序列分析对目标细菌和真菌菌株进行分子鉴定,并开展单因素实验对复合菌群的降油培养条件进行优化。结果表明:目标细菌和真菌对石油烃具有一定的降解能力,其降解率分布在17.19%~52.01%;而复合菌群S9(由B2、F4和F5菌株组成)对石油烃的降解率在第7 d可达到60.34%,比单一菌株在相同时间内降解率分别提高了11.03%、17.94%、8.33%。经鉴定,B2为假单胞菌(Pseudomonas)、F4为波氏假阿利什霉菌(Pseudallescheria boydii)、F5为尖端赛多孢子菌(Scedosporium apiospermum)。经培养条件优化后,S9接种量为7.0%(B2占2.0%,F4占2.5%、F5占2.5%)、初始石油质量分数为1%、温度为30℃、pH为7、转速为140 r·min^(-1)的条件下,第7 d对石油烃的降解率可达84.37%,相比优化前提高了24.03%,降解能力提高显著,达到了预期目的。

To obtain a bacterial-fungal composite community which can degrade petroleum hydrocarbons efficiently,the preliminary screening was conducted by comparing the degradation rates of individual strains.The two highest-performing bacteria and two fungi were selected for further experiments.Subsequently,a combination of methods including compound formulation and orthogonal design was employed to construct a composite community with optimal petroleum hydrocarbon degradation capability.Molecular identification of the target bacteria and fungi strains was carried out using 16S rRNA and ITS sequencing analysis.Additionally,single-factor experiments were conducted to optimize the cultivation conditions for the composite community.The results demonstrated that the target bacteria and fungi exhibited certain levels of degradation ability towards petroleum hydrocarbons,with degradation rates ranging from 17.19%~52.01%.Notably,the composite community S9,consisting of strains B2,F4,and F5,achieved a degradation rate of 60.34%on the 7th day,surpassing the degradation rates of individual strains by 11.03%,17.94%,and 8.33%,respectively,within the same time frame.The identified strains were B2(Pseudomonas),F4(Pseudallescheria boydii),and F5(Scedosporium apiospermum).After optimizing the cultivation conditions,the composite community S9 demonstrated an 84.37%degradation rate towards petroleum hydrocarbons on the 7th day under the following conditions:inoculation rate of 7.0%(B2 at 2.0%,F4 at 2.5%,and F5 at 2.5%),initial petroleum mass fraction of 1%,temperature of 30℃,pH of 7,and agitation speed of 140 r·min^(-1).This represented a significant improvement of 24.03%compared to the pre-optimized conditions,indicating a remarkable enhancement of degradation capability.