Study On The Action Mechanism Of Improving H₂ Photoproduction In Chlorella Pyrenoidosa By High CO₂ In The Background Of NaHSO₃ Treatment

With increasing environmental pollution and energy crisis,how to explore clean and alternate energy source becomes more and more urgent.Photobiological hydrogen production by microalgae has become one of hot issues in energy field because of its clean and carbon-free renewable source.Appropriate concentration of NaHSO3 can improve the H2 photoproduction of microalgae,which is one of the most effective and convenient methods for preparing hydrogen by microalgae.However,the method still has some shortcomings,such as NaHSO3 treatment seriously weakened the activity of PSII,etc.,which should to be further optimized.In this paper,the effect of CO2 on the H2 photoproduction of Chlorella pyrenoidosa was optimized and its possible mechanism was explained.Our results showed that,on the one hand,treatment with NaHSO3 can result in an approximately 40-fold increase in hydrogen photoproduction in Chlorella;compared with the air culture,high concentration of CO2 significantly promoted the growth rate and biomass accumulation of Chlorella,and the amount of H2 was doubled after treatment with NaHSO3.The results shoesd that treatment with high concentration of CO2 significantly increased the biomass of Chlorella,then improved the H2 photoproduction of Chlorella.On the other hand,under the same conditions of algal cell density and NaHSO3 treatment,the mount of H2 photoproduction of Chlorella treated with the high concentration of CO2 was about 1.3 times higher than that of air,and further study indicated that high concentration of CO2-treated Chlorella could maintain a higher PSII activity,that is,to maintain a more adequate source of electrons.In summary,we first found that under the background of NaHSO3 treatment,high concentration of CO2 can improve the activity of PSII for improving the H2 photoproduction of Chlorella.The results of this study not only provide a new research method for the use of NaHSO3 to improve the H2 photoproduction of microalgae and find a new way to turn waste into treasure,but also lay the theoretical foundation for the future large-scale industrialized application of the H2 photoproduction of microalgae.