Biosorption characteristics of a highly Mn(II)-resistant Ralstonia pickettii strain isolated from Mn ore

Abstract

Microorganisms play an important role in immobilizing and detoxifying excessive Mn; however, there is so far a lack of sufficient information concerning highly Mn(II)-tolerant bacteria. The present study was conducted to analyze the bio-sorption characteristics of a strain (HM8) isolated from manganese ore wastes. Analytical data from the 16S rDNA sequence determination showed that the species, HM8, had a 99% similarity to Ralstonia pickettii. Results from the designed physiological, biochemical and isothermal adsorption tests indicated that HM8 did not only grow well at a Mn(II) concentration level of 10,000 mg/L but also removed 1,002.83 mg/L of Mn(II) from the bulk solution of the culture, showing that the isolated strain possessed strong capabilities to tolerate and remove Mn(II). In the isothermal bio-sorption experiments performed to investigate the effects of relevant factors on Mn(II) sorption, the highest Mn(II) removal rate was obtained at the contact time 72 h, temperature 40°C, and pH 6.0, while the differences in both strain growth and Mn(II) removal rate between different inoculated HM8 doses were found to be insignificant within the tested range. Scanning electron microscopy showed that, under Mn(II) stress, HM8 cells appeared irregular and cracked, with apparent wrinkles on the surface. The peaks in the Fourier transform infrared spectra showed that hydroxyl and carboxyl groups were the main functional groups for Mn(II) adsorption. The experimental data supported the practical application of HM8 as a biological adsorbent for remediation of heavily Mn contaminated sites.

Structural Changes of Bacillus subtilis Biomass on Biosorption of Iron (II) from Aqueous Solutions: Isotherm and Kinetic Studies

“…4 and 5). Similarly, the alteration in morphology of Ralstonia pickettii and lactic acid bacteria biomass was observed due to biosorption of Mn (II) and Fe (II), respectively (Ramyakrishna and Sudhamani 2017;Huang et al 2018).…”

A high Mn(II)-tolerance strain, Bacillus thuringiensis HM7, isolated from manganese ore and its biosorption characteristics

“…H1(2650 mg/L) was much lower than that of HM7(4000 mg/L). In our previous project, three Mn(II) tolerant strains (B. cereus HM5, B. thuringiensis HM7, R. pickettii HM8) was isolated, the Mn adsorption capacity and characteristics of these strains were studied ( Huang et al, 2018 ; Xu et al, 2019 ). The maximum survival concentration and adsorption characteristics of the above strains were different ( Table S1 ).…”

Peer Review #2 of "A high Mn(II)-tolerance strain, Bacillus thuringiensis HM7, isolated from manganese ore and its biosorption characteristics (v0.1)"

“…H1(2650 mg/L) was much lower than that of HM7(4000 mg/L). In our previous project, three Mn(II) tolerant strains (B. cereus HM5, B. thuringiensis HM7, R. pickettii HM8) was isolated, the Mn adsorption capacity and characteristics of these strains were studied (Huang et al 2018;Xu et al 2019). The maximum survival concentration and adsorption characteristics of the above strains were different (S Table 1).…”