Zinc Oxide Nanoparticles Enhance the Tolerance and Remediation Potential of Bacillus spp. against Heavy Metal Stress

Table 2

Effect of different concentrations of green synthesized ZnO nanoparticles (0, 5, 10, 15, 20, and 25 ppm) on colony-forming unit (CFU) of Bacillus cereus and Lysinibacillus macroides under heavy metal (Pb, Cd, Cr, and Cu) stress.

Treatments	Bacterial growth (colony-forming unit) (cells/mL)
	Control (+)	Lead	Chromium	Cadmium	Copper
Bacillus cereus
Control (HMs) (-)	^ab	^efg	^ij	^efg	^hi
5 mg/L ZnO NPs	^ij	^b	^efg	^cd	^cde
10 mg/L ZnO NPs	^ij	^a	^def	^bc	^cd
15 mg/L ZnO NPs	^bc	^bc	^ij	^fg	^hi
20 mg/L ZnO NPs	^a	^ijk	^ijk	^gh	^jk
25 mg/L ZnO NPs	^ab	^kl	^ab	^lm	^mn
Lysinibacillus macroides
Control (HMs) (-)	^bc	^c	^ij	^hi	^fgh
5 mg/L ZnO NPs	^a	^b	^efg	^cde	^ef
10 mg/L ZnO NPs	^bc	^a	^def	^cd	^de
15 mg/L ZnO NPs	^ijk	^b	^ij	^hi	^ghi
20 mg/L ZnO NPs	^efg	^d	^ijk	^jk	^jk
25 mg/L ZnO NPs	^cd	^efg	^mn	^n	^i

Values are of three replicates () followed by different alphabetic letters which showed statistically significant at 5% probability level (ANOVA and Duncan’s multiple range test).