Study On The Oxidative Activities Of Microalgae Under Adverse Environmental Stress Based On Single Cell Instrument Combined With Confocal Raman

Microalgall,a primitive and ancient living,has many species,which exist a wide range of physiological and biochemical properties.What more,Microalgal can produce many unique fats,polysaccharides,proteins,carotenoids and other biologically active substances,which have a important development value in medicine,energy,water purification and other fields,and have been widely cultivated and developed.This paper researched the oxidative stress response of Scenedesmus obliquus at the single cell level under Na Cl and PEG6000stress by the single cell instrument combined with a confocal Raman instrument,and explored the response mechanism of salt and osmotic stress in the growth of Microalgal.Finally,it could be found that it had great potential to use Microalgall as a biosensor to identify water quality.The main research contents were as follows:（1）The research explored a new electrochemical detection method for detecting H₂O₂produced by Microalgal.The pre-experiment verified that the substance produced by Scenedesmus obliquus was H₂O₂by adding DPI and CAT,meanwhile,the standard relationship was established between the current and H₂O₂.In five groups of different concentrations of Na Cl and five groups of PEG6000 solutions with the same osmotic potential,it was found that the H₂O₂produced by Scenedesmus obliquus ranged from 0.017 to4.076μM（Na Cl）and 0.001 and 9.278μM（PEG6000）,the currents of the released H₂O₂was 264.9 and 577 p A in the two groups of largest response,meanwhile,changes of the microalgal cell morphology was observed in the real-time,especially in high-concentration solutions.（2）A confocal Raman micro spectrometer was used to acquire the Raman spectra of the single-celled of Scenedesmus obliquus under adversity stress,meanwhile,visualization of microalgal cells were explored.It was found that microalgal cells had different metabolic differences in a short-term adverse environment.Carotenoids and other pigments,the consumption of antioxidants would increase with the degree of oxidative stress,while the content of chlorophyll would reduce with the degree of oxidative stress,which illustrated that the normal metabolism of cells was affected severely.Further,it could be found that the concentration and distribution of chemical components had a quite different in the cells by cluster analysis of microalgal cells.When the damage was more severe,the cell content distribution was more disorder to cause cell death.（3）It was found that microalgal could be used as biosensors to monitor the salt stress problem of water quality by the analysis of microalgal cells under different adversities.Different models had been established to compare by the extraction of the full band and different characteristic bands,and it was found that the full band combined with LS-SVM model could achieve a classification accuracy of 57.3%,while SPA-LS-SVM could achieve an accuracy of 55.2%in the extraction of characteristic wavelengths.（4）The CAT activity of microalgal was studied under adversity by the enzyme-labeled instrument.The CAT activity under Na Cl and PEG6000 was significantly increased to 1.305and 1.543 U/ml,and the results were compared with the test results of a single cell analyzer.It was found that there was a certain degree of similarity by comparing and fitting.The difference was mainly due to the difference in adaptability to the environment between single cells and population cells,but the overall trend was the same,meanwhile it also proved the effectiveness of the single cell instrument method.As a biologically valuable organism,it has great significance for exploring the life forms and physiological responses of microalgae to the expansion of species cultivation and high-quality harvest to human development.