Bioaccumulation, Resistance, Removal of U(VI) and Th(IV) and Their Effects on Antioxidant Enzymes on Thermophilic Anoxybacillus flavithermus ST15

Abstract

In this research, a novel heavy metals resistance thermophilic Anoxybacillus flavithermus ST15 was isolated from a hot spring mud sample in Afyonkarahisar (Omer). 16S rRNA analyzing revealed that strain ST15 was 99.7% similar to Anoxybacillus flavithermus subsp. yunnanensis str. E13. We propose that U(VI) and Th(IV) have an effect on A. flavithermus at the cellular level and that this bacteria can be used as a bioindicator. Therefore, the effects of U(VI) and Th(IV) resistance, removal, and bioaccumulation on the antioxidant enzyme systems of thermophilic A. flavithermus have been thoroughly investigated. SOD and CAT activities were observed to be increased by different concentrations of U(VI) and Th(IV). A scanning electron microscope and fourier transform infrared spectroscopy were used to analyze changes in the surface macrostructure and functionality of A. flavithermus following interaction with U(VI) and Th(IV). The highest bioaccumulation efficiency amounts for U(VI) were 102.36 mg/g dried bacteria at 24 h at 12.5 mg/l concentration and 105.7 mg/g dried bacteria at 36 h at 12.5 mg/l concentration was detected for Th(IV). At the 24th h and 12.5 mg/l, the highest U(VI) and Th(IV) cell membrane bioaccumulation capacities of A. flavithermus were calculated as 307.08 and 289.52 mg metal/g wet membrane, respectively. This is the first research to examine U(VI) and Th(IV) resistance, removal, and bioaccumulation in thermophilic A. flavithermus.