https://nova.newcastle.edu.au/vital/access/ /manager/Index en-au 5 https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:34502 2+ removal by three PNSB strains; Rhodovulum sulfidophilum SRW1–5, and Afifella marina strains SSS2-1 and SSW15-1, grown with 2 different growth conditions (microaerobic light and aerobic dark conditions) were tested (2 mg/L HgCl₂, 4.5 mg dry cell weight/mL, 30 min). It was found that the efficiency to remove Hg²⁺ by the dead cells of all strains was significantly higher than for live cells; and the most effective strain was SSS2-1. The highest Hg²⁺ removal under the optimum conditions using a 4 mg/L initial HgCl₂ concentration by live and dead cells grown with both incubation conditions were approximately 87% and 95%, respectively. Under both incubation conditions, Hg²⁺ biosoption by strain SSS2-1 fitted the Freundlich model for live cells and the Langmuir model for dead cells. The kinetics of Hg²⁺ biosorption by both cell types of strain SSS2-1 suggests the process as a pseudo-second order kinetic model. This study demonstrates that biomass of the strain SSS2-1 has great potential for its biosorption to remove Hg²⁺ from contaminated areas like shrimp ponds.]]> Wed 04 Dec 2019 11:27:09 AEDT ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:36508 Rhodopseudomonas palustris C₁ and Rubrivivax benzoatilyticus C₃₁ to ameliorate As toxicity and to reduce As uptake in rice. Strain C₁ was superior to strain C₃₁ for siderophore production. The mixed culture (1: 1) was most effective in reducing the toxicity of As species [As(III) and/or As(V), each 30 mg/l] by yielding maximal germination index that related to α- and β-amylase activities in two Thai rice cultivars (HomNil: HN and PathumThani 1: PT). Arsenic toxicity to the seed germination followed the order: mixed As species > As(III) > As(V); and the toxicity was reduced in inoculated sets, particularly with a mixed culture. The mixed culture significantly enhanced rice growth under As stress in both rice cultivars as indicated by an increase in the production of chlorophyll a and b, and also supporting the non-enzymatic (carotenoids, lipid oxidation, and nitric oxide) and enzymatic (superoxide dismutase, ascorbate peroxidase, catalase, and glutathione reductase) activities. These were concomitant with productions of 5-aminolevulinic acid, indole-3-acetic acid, exopolymeric substances, and siderophores which significantly reduced As accumulation in treated rice. It can be concluded that the mixed culture has great potential to ameliorate rice from As toxicity by preventing As species entry into rice for enhancing rice growth and also for reducing As accumulation to produce safe rice from rice grown in contaminated paddy fields.]]> Mon 25 May 2020 12:29:48 AEST ]]>