Studies On Spergillus Oryzae AS 3.951 And Trametes Gallica D2 Of Chromium Enriched And Adsorption

The enrichment of metals by microbial method has become a research hotspot,which fit in with the development trend of green chemistry.In this paper,the characteristics of enrichment of chromium ion by Aspergillus oryzae AS3.951 and Trametes gallica D2 were studied.This paper found the best Aspergillus oryzae growth conditions: yeast extract 1.5%,sucrose 3%,adding inorganic salt,temperature of 30 ?,the volume was 50 mL,pH was 6,the rotation speed was 140 r/min.There was a great difference in growth and accumulation ability of Aspergillus oryzae under Cr³⁺ and Cr⁶⁺ environment pressure.This research showed that Aspergillus oryzae had strong tolerance on Cr³⁺ treatment,and has better ability of chromium enrichment?0.128 mmol/g?;Cr⁶⁺ of poor tolerance,weak enrichment.On the condition of Aspergillus chromium response surface analysis,and ultimately determine the enrichment conditions were: sucrose 30.68 g/L,yeast extract 15.61 g/L,liquid volume 56.93 mL/250 m L,pH 6.5,Cr³⁺ concentration 3 mmol/L.By using scanning electron microscopy?SEM?,transmission electron microscopy?TEM?and Fourier transform infrared spectroscopy?FITR?method,we determined the basic binding site of Aspergillus oryzae and chromium mainly concentrated in the cell wall,inside the cell containing a small amount of metal.The adsorption data showed that the adsorption process of Cr³⁺ was consistent with pseudo two order reaction rate equation and Langmuir adsorption model.The experiment found that four kinds of surface active agent?sucrose fatty acid ester,Twain 80,surfactin,SDS?could promote the enrichment of Cr³⁺ by Trametes gallica and the surfactin?sodium salt?had the most obvious promoting effect.In pH 7.5,0.2 mmol/L surfactant,2 mmol/L Cr³⁺,30?,rotation speed of 140 r/min,the volume was 60 m L,Trametes gallica on Cr³⁺ accumulation ability was significantly.Surfactin could increase Trametes gallica cell permeability,so that it could promote the Cr³⁺ enrichment process.