Isolation, identification, and fenvalerate-degrading potential of Bacillus licheniformis CY-012

Figures & data

Table 1. Results of Box–Behnken experimental design.

Run	X1	X2	X3	Y (%)
1	0	1	−1	71.35
2	0	1	1	72.93
3	−1	0	−1	76.49
4	1	0	−1	69.45
5	1	1	0	67.42
6	0	0	0	78.69
7	−1	−1	0	75.46
8	0	0	0	78.99
9	0	0	0	79.12
10	0	−1	−1	73.72
11	−1	1	0	75.58
12	0	−1	1	72.50
13	1	0	1	70.36
14	1	−1	0	68.54
15	−1	0	1	78.04

X₁: Fenvalerate concentration (mg L⁻¹), −1 (40), 0 (50), 1 (60); X₂: pH, −1 (6.0), 0 (7.5), 1 (9.0); X₃: Ferric chloride concentration (%), −1 (0.04), 0 (0.05), 1 (0.06).

Figure 1. Phylogenetic tree based on 16S rDNA sequences of strain CY-012.

Table 2. Variance analysis of the results from the Box–Behnken test.

Source	DF	SS	MS	F value	P value
Model	9	216.918	24.1020	155.46	0.000
One-term	3	113.079	37.6932	243.13	0.000
Two-term	3	101.391	33.7971	218.00	0.000
Interaction	3	2.447	0.8156	5.26	0.053
Residual error	5	0.775	0.1550
Missing term	3	0.678	0.2260	4.65	0.182
Pure error	2	0.097	0.0486
Total	14	217.693

DF, degrees of freedom; SS, sum of sequences; MS, mean square.

*P level less than 0.05 indicates the model terms are significant.

Figure 2. Three-dimensional plots and contours of the quadratic model for fenvalerate degradation by strain CY-012. [1] Response surface (A-1) and contour map (A-2) of the fenvalerate degradation rate (Y, %) as a function of the fenvalerate concentration (X₁) and pH (X₂) at a fixed concentration of ferric chloride (X₃) of 0.051% (w/v). [2] Response surface (B-1) and contour map (B-2) of the fenvalerate degradation rate (Y, %) as a function of the concentrations of ferric chloride (X₃) and fenvalerate (X₁) at a fixed pH value (X₂) of 7.48. [3] Response surface (C-1) and contour map (C-2) of the fenvalerate degradation rate (Y, %) as a function of the concentration of ferric chloride (X₃) and pH (X₂) at a fixed fenvalerate concentration (X₁) of 44.04 mg L⁻¹.

Figure 3. GC–MS chromatogram of metabolites of fenvalerate degraded by B. licheniformis CY-01.

Table 3. Chromatographic characteristics of the products of fenvalerate degradation by Bacillus licheniformis CY-012.

Serial number	Retention time (min)	Similarity(%)	Chemical formula	Chemical compound
A	3.250	80	C6H6O	Phenol
B	6.583	68	C7H6O2	Benzoic acid
C	14.767	65	C8H7ClO2	4-Chlorobenzene acetic acid
D	15.867	91	C11H13ClO2	α-Isopropyl-4-chlorobenzene acetic acid
E	19.650	91	C13H12O2	3-Phenoxybenzyl alcohol
S	24.925	76	C25H22ClNO3	Fenvalerate

Figure 4. GC–MS chromatogram of metabolites of 3-PBA degraded by B. licheniformis CY-012.

Table 4. Chromatographic characteristics of the degradation products of 3-PBA generated by Bacillus licheniformis CY-012.

Serial number	Retention time (min)	Similarity (%)	Chemical formula	Chemical compound
a	3.250	97	C6H6O	Phenol
b	4.325	57	C7H8O	Benzoic alcohol
c	19.725	74	C13H12O2	3-Phenoxybenzyl alcohol

Table 5. Degradation of intermediate metabolites.

Metabolites	Control (mAU·s)	Experiment (mAU·s)
4-Chlorobenzene acetic acid	2,861,686	285,736
Phenol	41,608,215	4,249,185
Benzoic acid	4,950,235	159,610

Figure 5. Proposed metabolic pathway of fenvalerate degradation by B. licheniformis CY-012.

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