Screening And Identification Of Manganese Oxidizing Bacteria,Manganese Oxidizing Characteristics And Immobilized Manganese Removal

Manganese oxidizing bacteria are an important environmental microbial resources.The bacteria and the manganese oxide they produced have great application potential in treatment of polluted water.In order to find new resources of manganese oxidizing bacteria and to investigate the feasibility of their application in actual water treatment,this study enriched,separated and purified 6 manganese strains,named H1,H2,H3,H4,H5,H6 with manganese oxidation ability from the soil of Chongzuo Manganese Mine.The strains were classified by 16S r RNA gene sequence alignment and evolutionary tree construction.Then,the morphology and structure of the manganese oxidation products produced by six strains of manganese oxidizing bacteria were analyzed by SEM-EDS and XRD analysis,to provide basic informations of these 6 manganese oxidizing bacteria for their further applications in environmental management.Finally,the strains H5 and H6 with high manganese tolerance were fixted as the capsules and the fixed strains H5 and H6 were used to treat manganese-containing industrialwastewater.Through orthogonal experiments,the optimal manganese removal conditions of the two capsule-fixing bacteria were determined,and the reusability of the capsule-fixing bacteria was studied to provide a basis for its practical application in manganese-contaminated wastewater.The main achievements of the paper are as follows:(1)6 strains of purified manganese bacteria have different ablity of manganese oxidation.According to th result of 16S r RNA.H1 is Burkholderia sp.,strain H2 and strain H5 are closest to Bacillus megaterium PCWCW5 and Bacillus megaterium SX11 in the database,respectively,H3 is Lysinibacillus fusiformis,H4 is Curtobacterium sp.,H6 as Stenotrophomonas maltophilia sp..(2)After cultivating in the manganese-containing medium,except for the H4strain,the other five strains of manganese-oxidizing bacteria produced manganese-containing sediments with a certain difference in morphological quantity between the cell surface and the cells.XRD analysis showed that 6 manganese oxidizing bacteria may form manganese compounds with different structures in the body and on the body surface,of which H3 and H4 manganese oxidation products are amorphous or amorphous;H1,H2,H5 and H6 mainly produce Mn CO₃.(3)The 6 manganese oxidizing bacteria all have a certain ability to remove Mn²⁺in the medium,and the H5 and H6 strains have the most significant ability to remove Mn²⁺.When Mn²⁺concentrations were 650 and 488 mg/L,bacteria strains H5 and H6 of manganese removal of 54.95%and 88.20%,respectively..(4)Capsule-fixing bacteria H5 and H6 have significant removal effects on Mn²⁺in wastewater.The maximum manganese removal efficiency of capsule-fixing bacteria H5 reached 96.33%at following conditions:Mn²⁺50 mg/L,activated carbon dosage of 0.75%,p H=8.0,and a treatment time of 2 d.The maximum manganese removal efficiency of capsule-fixing bacteria H6 reached 96.37%at following conditions:Mn²⁺250 mg/L,activated carbon dosage of 0.75%,p H=7.0,and a treatment time of 2 d.In addition,the capsule-fixed bacteria H5 and H6 have a certain degree of reuse.Under the optimal treatment conditions,after three rounds of reuse tests,the manganese removal efficiency of capsule-fixed manganese oxidizing bacteria H5 and H6 is still 59.73%and 34.60%.