PurposeTo study the bacterial community structure in the biofilm of Typha angustifolia under different mass concentrations hexaehlorobenzen (HCB) stress.
MethodBiofilm morphology on root of T. angustifolia was monitored by using SEM and 16S rDNA gene of the bacteria by high-throughput sequencing used root samples under different mass concentrations (38 and 760 μg/L) HCB stress.
ResultThe results of SEM showed that the microorganisms attached to the root biofilm were elliptic or rod-shaped. After different mass concentrations of HCB treatment, the amount of microorganisms attached to T.angustifolia roots increased obviously, with the increase of HCB mass concentration in water, a small quantity of bacteria inhabited the biofilm. The results of high-throughput sequencing revealed that the dominant phyla of bacteria were Proteobacteria, Actinobacteria, Chloroflexi, Cyanobacteria and Firmicutes. At the genus level, the dominant bacteria mainly included three categories: 1) photosynthetic bacteria of efficient water purification, such as Rhodomicrobium, Rhodopseudomonas, Rubrivivax, Rhodoblastus and Rhodobacter; 2) organic pollutant-degrading bacteria population, including Comamonas, Variovorax, Acinetobacter and Acidovorax; 3) denitrifying bacteria population, which joined denitrification and nitrogen cycle, such as Variovorax, Comamonas, Desulfovibrio, Rhodobacter, Acinetobacter, Mesorhizobium and Rubrivivax. PICRUSt functional prediction showed that bacteria in the biofilm had strongest functions in carbohydrate, amino acid and energy metabolism.
ConclusionThe abundance and diversity of bacterial communities in the biofilm under 38 μg/L HCB were higher than 760 μg/L HCB treatment. In addition, the dominant bacteria at the genus level may be related to eutrophication water purification, organic degradation, denitrification and nitrogen cycle. These results provide a theoretical basis for the removal mechanism of pollutants in eutrophic water.
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