Magnetic/Electric Field Regulating The Growth Of Tribonema Sp.and Its Application In The Recycling Of Food And Chemical Wastewater

Microalgae would be affected by environmental factors and biological factors such as rotifers,bacteria and other microorganisms during the growth of the open culture system.In order to improve the growth rate of microalgae and overcome the problems of microbial pollution,electromagnetic field intervention is introduced during the cultivation of microalgae.Electromagnetic fields as a physical processing method,having the advantages of low cost and no chemical substances.They are becoming an effective method to stimulate the growth and metabolism of microalgae cells and increase biomass accumulation.In the experiment,the easy-to-harvest filamentous Tribonema sp.was selected as the algae species,which is rich in oil content,trying to promote the growth of microalgae through electromagnetic field intervention and apply it to the wastewater treatment of food and chemical industry.The main content of the paper is as follows:(1)Explore the effects of different electric fields,magnetic fields and magnetic/electric composite field strengths on Tribonema sp.,studies had found that the electric field strength in the range of 0.3 V/cm-0.6 V/cm has signs of promoting the growth of algae.The biomass is higher when the field strength was 0.6 V/cm,which increases by 6.26%compared to the control,but when the field strength was0.9 V/cm,the biomass decreased;Magnetic field intervention did not significantly increase biomass accumulation;Compared with the control,the biomass of the magnetic/electric composite field 24 h/d-0.6 V/cm and 1 h/d-0.6 V/cm group increased by 12.8%and 21.54%respectively.It is obvious to change under the magnetic/electric composite field intervention treatment and the carbohydrate content can be increased by 23.08%.(2)Through transcriptomics sequencing methods,the differential expression of Tribonema sp.metabolic pathway genes under different electromagnetic field interventions was analyzed,It was explored from lipid metabolism,sugar metabolism,pigment synthesis and so on.Studies had shown that there are significant differences in the gene expression of Tribonema sp.metabolic pathway under different electromagnetic field interventions,the results are consistent with the compound content.The number of differentially expressed genes under the intervention of magnetic/electric compound field was far greater than that of electric field or magnetic field.Among them,the magnetic/electric compound field treatment group under the intervention of 1 h/d-0.6 V/cm promotes fatty acid biosynthesis and weakens the?-oxidation process;Compared with the intervention of electric field 0.6V/cm,the compound field of 1 h/d-0.6 V/cm can promote the process of gluconeogenesis and increase the accumulation of carbohydrates.Under the intervention of 1 h/d-0.6 V/cm,compared with the control,electric field 0.6 V/cm and magnetic field 1 h/d,carotene increased by 15.9%,5.82%,3.1%respectively.(3)Explore the interference of electromagnetic fields in the resource utilization of Tribonema sp.in food and chemical wastewater.The results show that the removal rate of COD was 76%-82%under different electromagnetic fields intervention,and the removal rate of TN,TP and NH₃-N more than 90%;For the refractory benzene substances in wastewater,when the electric field strength increases,the removal rate can reach more than 90%,the degradation rate can be increased under the intervention of magnetic/electric composite field.Under different electromagnetic field,Using high-throughput sequencing technology to explore the diversity analysis of the microbial flora in the open culture system,it shown that the microbial flora structure changes significantly in the magnetic/electric composite field compared with the interference of electric or magnetic fields.Electric field intervention is conducive to the accumulation of Flavobacterium abundance,while the magnetic/electric composite field had a dramatic impact on the abundance of bacteria in wastewater,promoting the gradual increase of Ancylobacter abundance as well.