Figure 2

Figure 2

The antibacterial activity of extracts (10 μg mL⁻¹) against Gram (−) bacteria. The different algal groups selected are indicated. The bacterial growth was evaluated by measuring the OD600 nm for 24 h; (A) The kinetics obtained in samples treated with the extract 9 was selected as representative result. T-test was used to determine significant differences at p-value < 0.05 (*). (B) Tables show the sampling points where the differences in OD600 nm were statistically significant at p < 0.05 against A. hydrophyla. The percentage of bacterial growth reduction is specified in each sampling point.