Isolation, Identification And Reduction Properties Of Fe (Ⅲ)/Reduction Properties Of Humic-reducing Bacteria

Fe (Ⅲ)/humus reduction is a recent discovery of new microbial anaerobic respiration form. It involved biogeochemical cycle of iron, and closely related with detoxification of organic pollutants and cycle of soil nutrients, etc. Fe (Ⅲ)/microbial humus reduction function is considered to be the key to the reduction process, become the focus of research. The Fe (Ⅲ)/reduction properties of humic-reducing bacteria were isolated from paddy soil, flooded soil, bank of river and sediment of seabed etc. However, it had been reported rarely that Fe (Ⅲ)/reduction properties of humic-reducing bacteria were isolated from cassava dregs composting. Three facultative anaerobic humus-reducing bacteria were isolated from cassava dregs composting. We chose HN01which had reduction effect obviously to research its reduction properties further more. The Fe (Ⅲ)/reduction properties of humic-reducing bacteria were researched. And the main results are as follows:(1) Analysis of physiological and biochemical characteristics and16S rDNA of HN01, HN02and HN03indicated that the closest phylogenetic relative among the valid species was Kocuria rosea, Arthrobacter tecti and Pseudomonas sp respectively.(2) The optimum culture conditions for these3strain was as follows:HN01grew well when the concentration of sodium chloride was1%, the incubation temperature was25℃and the pH value was8.0. HN02grew well when the concentration of sodium chloride was1%, the incubation temperature was30℃and the pH value was between7.5to8.5. HN03grew well when the concentration of sodium chloride was0.5%and the incubation temperature was30℃and the pH value was between6.5to7.5.(3) HN01could use glucose, sucrose, menthol, ethanol and glycerol as electron donor reduce AQDS and reducing power from large to small was glucose, sucrose, menthol, ethanol and glycerol. When the pH value was9.0or the concentration of sodium chloride was12%the reducing rate of AQDS was the highest.(4) HN01could reduce all three types of Iron oxide and reducing power from large to small was goethite, lepidocrocite and hematite. The content of total ferrous iron was0.16,0.087and0.066mmo·L-1respectively.(5) HN01have different reduction efficiency to4kinds of chlorine-containing compound y-HCH, p’p-DDT, o’p-DDT and2,4-D. The reduction effect of HN01on p’p-DDT was obvious, with a degradation efficiency of71.3%and HN01cannot degrade the other three kinds of chlorine-containing compound.