## 3 Results and Discussion
### Evaluation of the Ability of Strain Q3-6 to Decolorize Dyes
#### 3.7.2 The Effect of Different Initial Concentrations of Dyes on Decolorization  
The dye decolorization ability of strain Q3-6 was investigated at different initial Brilliant blue G-250 concentrations (100-500 mg/L). As shown in Figure 5, the decolorization ability of strain Q3-6 gradually decreased with the increase in dye concentration. When the concentration of dye was 0.1 g/L, the dye decolorization rate reached 93.9%. When the concentration of dye was 0.5 g/L, the decolorization rate also reached 65.3%. One-way  
Figure 3: Effect of heating and secondary heating on bacterial population (different lowercase letters represent significant differences (\(p<0.05\))).  
ANOVA analysis of the results showed that the dye concentrations of different groups at the same time point were significantly different (\(p<0.05\)), indicating that the initial concentration had a great effect on the decolorization progress. [PERSON] and [PERSON] [75] found that the decolorization effect decreased with increasing dye concentration. [PERSON] et al. [76] showed that _Bacillus argabhattai_ can decolorize CBB G-250 up to 150 mg/L. The results of the present studies clearly indicate that the treatable concentration of Brilliant blue G-250 has been documented to be as high as 500 mg/L for strain Q3-6, and strain Q3-6 has superior decolorization ability, with good results in terms of treatable concentration as well as treatment time.  
7.3 The Effect of Salinity, Pondus Hydrogenii, and Temperature on the Decolorization of Brilliant Blue G-250 Dye  
From the experimental results in Figure 6, it can be seen that the highest decolorization (60.2%) of Brilliant blue G-250 by strain Q3-6 was achieved at 1% salinity, whereas higher salinity (4%) resulted in a significant decrease in decolorization. This phenomenon may be related to the fact that higher salinity will inhibit the growth of the strain, which is consistent with the results of the previous experiments in this study. In addition, this phenomenon may also be due to competition for adsorption sites between Na (I) and the dye, so an increase in salt concentration leads to the removal of the dye [77].  
From the experimental results in Figure 7, it can be seen that the decolorization of Brilliant blue G-250 by strain Q3-6 reached its maximum (75.7%) when the pH was 6.5, and the acidic environment caused a significant decrease in the decolorization rate. The possible reason for this is due to the fact that H (I) in the acidic solution competes with the dye for adsorption sites [78]. This result indicates that strain Q3-6 has the best decolorization  
Figure 4: Decolorization of 0.15 g/L of Brilliant blue G-250.  
Figure 5: Quantification of the ability of Q3-6 to decolorize different concentrations of Brilliant blue G-250.  
effect in a neutral environment. Dyeing wastewater is in most cases weakly alkaline, and other studies have shown that neutral environments are more conducive to bacterial decolorization of dyes [25; 79].  
As shown in Figure 8, in the optimal temperature interval for the growth of strain Q3-6, the decolorization rate was relatively stable from 30 \({}^{\circ}\)C to 45 \({}^{\circ}\)C, with a small increasing trend with temperature and the decolorization rate up to 56.0% at 45 \({}^{\circ}\)C. While at 16 \({}^{\circ}\)C, strain Q3-6 could hardly decolorize Brilliant blue G-250. This result suggests that low temperature will significantly inhibit the ability of strain Q3-6 to decolorize Brilliant blue G-250. Within a certain range, the higher the temperature, the higher the surface activity, meaning that higher temperatures favor the biological removal of dyes [77]. The decolorization of Brilliant blue G-250 by strain Q3-6 in the present study was higher at 30-40 \({}^{\circ}\)C compared to the study of [PERSON] et al. [76].