Establishment Of Stable Culture And Optimization Of Symbiotic System Of Bacteria And Algae

As a widespread phenomenon of water pollution,the eutrophication of water has attracted people’s long-term attention.Water bloom,as a remarkable pinnacle of such issues,has always been the focus of research.Long-term studies have found that interactions between organisms other than nutrients may also be one of the causes of bloom outbreaks.There are many studies on the relationship between bacteria and algae,and they tend to have more research on the role of bacteria in the killing and inhibition of algae.There is less research on the relationship between bacteria and algae,and there are few basic research on the symbiotic system.Establishing a symbiosis system of bacteria and algae and stably cultivating it is of great significance for the in-depth exploration of the interaction between them and the interaction of intrinsic substances.In this paper,field surveys and literature surveys were conducted to select Anabanea flos-aquae,Synechocystis sp.,Roseomonas sp.,and Luteolibacter algae as target objects.A cross-over experiment was conducted to ascertain the ecological relationship between bacteria and algae.In this paper,the symbiotic system was evaluated by algae physiological indicators(cell count,chlorophyll a,photosynthetic oxygen release rate,chlorophyll fluorescence parameters,etc.),a symbiosis system was established,and the conditions of the system were optimized.This will provide basic research support for the study of the symbiotic mechanism of algae and bacteria,and provide new ideas for the causes of water bloom outbreaks.The main conclusions of the study were:① The maximum ratio of alga cells in the control group and the addition of Bacillus verticilliflora and Rhizoctonia sp.in the mixed system of bacteria and algae mixed with bacteria was 1:1.096:1.333;algae cells in Synechocystis sp.The maximum ratio was 1:1.136:1.25.It was found that the activity of R.rosenbergii was the largest for A.aquatica.At the same time,the dominant bacteria-algae symbiosis system was obtained through the combination of changes in bacterial biomass(bacteria in the experimental group of A.sinensis)were better than other groups,TOC,and other indicators combined with the scope of the screening.Bacteria.② In the study of optimization of the culture mechanism of the symbiosis system of bacteria-algae,the optimized solution for the medium was obtained by adding 40 mg/L glucose and 100 mg/L casein to BG11.Under the experimental conditions,the optimal ratio of bacteria and algae was 1:10.③ Influence of environmental factors on the symbiosis of bacteria-algae system.Different N:P effects on the system are very different.The optimum N:P ratio is 64:1 with 2.5 μmol/L phosphorus ion as the substrate concentration.According to the investigation of environmental factors,the condition is set to 25℃-30001ux,which is the optimal combination of stable operation of the system.This article also found that different temperatures have different starting times for the biomass outburst of the whole system,which shows that the temperature rises earlier than the temperature.And the biomass stability is inversely proportional to temperature after the outbreak,which may be of significance for revealing the features of the bloom explosion.