营养条件对氧化亚铁硫杆菌生长及其铁沉淀的影响研究

为减少氧化亚铁硫杆菌培养过程中沉淀的产生,对其营养条件进行优化,研究不同氮源、磷源、初始Fe2+质量浓度及pH值对菌体生长和沉淀量的影响。结果表明:最佳氮源(NH4)2HPO4质量浓度为1.5 g/L时,取代了(NH4)2SO4和K2HPO4,同时作为氮源和磷源;优化后的培养基初始Fe2+质量浓度为13.5 g/L,pH值为1.8。优化后培养条件下菌体生长有较高氧化活性且沉淀量少。

Study of the effects of culture condition on the growth of Thiobacillus ferroxidans and the jarosite precipitates

This paper is to explore the effects of culture condition on the growth of Thiobacillus ferroxidans and the related jarosite precipitates.For this research purpose,we have first of all studied the nutritional conditions,under which the Thiobacillus ferrooxidans behave with greater oxidation activity and less precipitation to reduce the blockage of filler surface caused by the growth of Thiobacillus ferrooxidans during the bio-trickling reactor removal of sulfur dioxide.In accordance with the mechanism of precipitation,it can be followed that the lower the concentration of cation of precipitation,the smaller the amount of precipitation would be.Next,we have mainly studied the different effects of nitrogen,phosphorus,pH and Fe2+ concentration on the germ growth and the impact of precipitation amount.So far as we know,the best nitrogen source is diammonium phosphate.Because of the effect of hydrogen phosphate,large amounts of ferrous hydroxide precipitates would come about in the cultural media with low solution pH value.However,if the nitrogen source is diammonia phosphate and hydrogen phosphate may buffer the germ growth in the environment,the possibility to produce great precipitation at the lower range of pH would be scarce.Of course,too much hydrogen phosphate also tends to affect the growth of the germ.Therefore,the optimal concentration of diammonium phosphate,as we have found,is only 1.5 g/L,which is supposed to be able to replace the ammonium sulfate and potassium hydrogen phosphate.Thus,it can be deduced that it would be better to reduce the concentration of ammonia ions and potassium ions so as to reduce the amount of precipitation and make the pH value more environment-feasible. That is the reason why we believe that 13.5 g/L is the higher concentrations of ferrous ions whereas the optimal initial pH should be 1.8,which may lead to higher oxidation activity and lower degree of precipitation.Under such conditions,it is possible to keep the germ growth with a greater cell density than that was before the optimization.Thus,our study has proven that under new culture conditions,it is conducive to greater industrial applications for the germ growth to come about at higher oxidation activities and lower precipitation.