Table 2.

Sensitivity of all bacterial strains to Titanium dioxide (TiO₂₎ in its dispersed form (P25-D in light green and E171-D in light orange).

		Lag time (h)		Specific growth rate μmax (h-1)		Final biomass (OD600nm)
Species	Strain	P25-D	E171-D	P25-D	E171-D	P25-D	E171-D
L. lactis	IBB477 subsp. cremoris	× 1.7	× 4.3	× 2.4	× 2.3	× 3.0	× 6.0
	TIL448 subsp. lactis	× 1.3	× 6.7	× 1.6	× 1.8	× 1.6	× 4.3
L. sakei	23K	× 1.1	× 1.3	× 1.4	× 1.5	× 1.7	× 2.9
S. thermophilus	LMD-9	× 1.3	× 1.8	× 2.3	× 2.0	× 1.7	× 4.3
L. rhamnosus	LGG	× 1.3	× 2.2	× 1.7	× 1.8	× 1.4	× 1.9
E. coli	K12 MG1655	× 3.8	NA	× 2.0	NA	× 3.6	NA
	ATCC8739	× 2.4	× 4.5	× 1.5	× 4.8	× 1.5	× 4.8
	CEC15	× 1.2	× 2.4	× 1.1	× 1.2	× 2.1	× 4.0
Significance		NS	∗∗	∗∗	∗∗	∗∗	∗∗

Three growth parameters have been considered: lag time (h), specific growth rate μ_max (h^-1) and final biomass (OD_600nm). Ratios have been calculated with the mean values obtained for the maximal TiO₂ concentration (320 μg/mL) vs. control conditions (no TiO₂ added); decrease, increase, NA, not available. Significance was determined for each growth parameter considering the overall P25-D- and E171-D-treated strains (except E. coli K12 MG1655) using one-way ANOVA corrected for multiple comparisons with Dunnett test: (^∗∗) indicates p < 0.01 compared to control conditions with no TiO₂ added (NS, not significant).