Effect Of Metal Nanoparticles On Biohydrogen Producted By Enterobacter Sp.HDX08 Bacteria During Anaerobic Fermention

Nanoparticles has been widely utilized in wastewater treatment and anaerobic biohydrogen production because of their large specific surface area and high surface activity,while the whole process is expected further analysis on its mechanism.This study used an ethanol-type fermentation hydrogen-producing dominant bacterium Enterobacter sp.HDX08 as research target,which was screened and purified by our research group,to optimize the hydrogen production condition and disscuss the optimum dosage of three kinds of metal nanoparticles?Fe₃O₄NPs?ZnONPs?AgNPs?.Then studied the effect of these nanoparticles on bacterial growth,cumulative hydrogen yields,hydrogen-producing rate and substrate degradation,so as to establish the biohydrogen dynamic model.The metabolite concentration,NADH,dehydrogenase and ferridoxin reductase activity of bacteria HDX08 during hydrogen production were analyzed by gas chromatography,three-dimensional fluorescence,uv-vis and enzyme labelling apparatus,and the mechanism of three kinds of metal nanoparticles on the hydrogen production of bacterial HDX08 fermentation was analyzed,and conclusion listed as follows:?1?The dominant hydrogen-producing bacteria were identified as Enterobacter sp.HDX08 by 16S rDNA sequencing.The optimum hydrogen production conditions of bacteria HDX08 are 8 of initial pH,10 g/L of initial glucose concentration.?2?When the concentrations of three metal nanoparticles,Fe₃O₄NPs,ZnONPs and AgNPs were less than or equal to 300 mg/L,200 mg/L and 3 mg/L,respectively,the growth and hydrogen production rate of HDX08 were promoted.among which150 mg/L of Fe₃O₄NPs has the strongest ability to promote hydrogen production,which can increase the hydrogen production rate by 85%.However,the addition of three kinds of metal nanoparticles will not change the fermentation type of HDX08.?3?The processes of hydrogen production and substrate degradation of three kinds of metal nanoparticles/bacteria HDX08 were well fitted by Gompertz and Logistic equations respectively.According to Gompertz parameters,after the addition of 150 mg/L of Fe₃O₄NPs,the system has the largest cumulative hydrogen production,the highest hydrogen production rate,and the shortest delay period of hydrogen production;According to Logistic parameters,150 mg/L of Fe₃O₄NPs can promote the complete consumption of glucose for hydrogen production.?4?150 mg/L Fe₃O₄NPs and 200 mg/L ZnONPs mainly stimulate the activity of ferritin reductase and coenzyme NADH,and 3 mg/L AgNPs mainly stimulate the activity of coenzyme NADH to promote the hydrogen production of ethanol-producing bacteria.