Biological characteristics and oxidation mechanism of a new manganese-oxidizing bacteria FM-2

Abstract

A new manganese-oxidizing strain FM-2 was screened out from biological activated carbon (BAC) filter column and was identified as Citrobacter freundii. The results of the systematic study on this species are as follows: At 27 , the optimum pH for Citrobacter sp. FM-2 to remove manganese was 7.0-8.0.The best removal rate of manganese under 27 , pH 7.0 by FM-2 was reached at 4 d, being 76.2%; Compared with adsorption, biological oxidation played a dominant role in this removing process. Almost 75.7% of manganese was oxidized into oxides by Citrobacter sp and there were some particular oxides analogs generated on the bacterial surface; A 296bp DNA fragment amplified from Citrobacter sp. FM-2 revealed that this species has multicopper oxidase genes. Meanwhile, the phylogenetic tree indicated that compared with other related species, Citrobacter sp. FM-2 has its own evolutional independence.

Autochthonous tropical groundwater bacteria involved in manganese(ii) oxidation and removal

“…These results are in agreement with previous findings for different MOB than the ones reported here, suggesting that during the stationary phase biological oxidation of Mn(II) takes place. 25,35,[66][67][68][69][70][71][72] In the second group of strains (HAC-3A, HAC-3B and RUE-6A), Fig. 2A, no further Mn(II) removal took place after the second day.…”

“…This increase in pH was probably related to bacterial growth and substance metabolism in a culture. 72 In bacteria with an abrupt increase in pH, the removal of Mn(II) could occur indirectly by favouring chemical oxidation, occurring at a pH above 8.0. 18,22,49 This e.g.…”

“…4B), which had greater Mn removal activity, the pH remained between 7 and 7.5 during most of the culture, with these values being the most favourable for the biological oxidation of Mn(II). 18,24,72 3.2 Biofilm formation capacity 3.2.1 Qualitative biofilm formation test. The biofilm formation capacity was evaluated in the seven strains selected from the results with LBB.…”

Screening, identification, and removal dynamics of a novel iron-manganese removal strain

“…In the author's previous work, a new manganese-oxidizing strain FM-2 was screened out from the biological activated carbon (BAC) filter column, which was identified as Citrobacter freundii [6]. In this paper, the author separated and screened an efficient strain FM-2, which had a good removal performance of iron and manganese from biological activated carbon (BAC), and conducted the test of identification by 16S rDNA sequence and physiological and biochemical experiments.…”