Microalgae biofilm formation and antioxidant responses to stress induce by Lemna minor L., Chlorella vulgaris, and Aphanizomenon flos-aquae

The study shows how microalgae biofilm formation and antioxidant responses to the production of reactive oxygen species (ROS) is alter by the presences of Lemna minor L., Chlorella vulgaris, and Aphanizomenon flos-aquae. The study involves the cultivation of the biofilm of Chlorella vulgaris and Aphanizomenon flos-aquae in three bioreactors. The condition of growth for the biofilm formation was varied across the three bioreactors to enable the dominance Chlorella vulgaris and Aphanizomenon flos-aquae in one of the bioreactors. Lemna minor L. was also introduce into one of the bioreactors to determine its effect on the biofilm formation. The result obtained shows that C. vulgaris and A. flos-aquae dominate the biofilm, resulting in a high level of H2O2 and O2- (H2O2 was 0.122 +/- 0.052 and 0.183 +/- 0.108 mmol/L in C. vulgaris and A. flos-aquae, respectively, and O2- was 0.261 +/- 0.039 and 0.251 +/- 0.148 mmol/L in C. vulgaris and A. flos-aquae, respectively). The study also revealed that the presence of L. minor L. tend to reduce the oxidative stress to the biofilm leading to low production of ROS (H2O2 was 0.086 +/- 0.027 and 0.089 +/- 0.045 mmol/L in C. vulgaris and A. flos-aquae respectively, and O2- was 0.185 +/- 0.044 and 0.161 +/- 0.065 mmol/L in C. vulgaris and A. flos-aquae respectively). The variation in the ability of the biofilm of C. vulgaris and A. flos-aquae to respond via chlorophyll, carotenoid, flavonoid, anthocyanin, superoxide dismutase, peroxidase, catalase, glutathione reductase activities, antioxidant reducing power, phosphomolybdate activity, DPPH reduction activity, H2O2 scavenging activity, lipid content and organic carbon also supports the fact that the presence of biomass of microalgae and aquatic macrophytes tend to affect the process of microalgae biofilm formation and the ability of the biofilm to produce antioxidant. This high nutrient utilization leads to the production of biomass which can be used for biofuel production and other biotechnological products.

Automated summary

The study demonstrates how the presence of Lemna minor L., Chlorella vulgaris, and Aphanizomenon flos-aquae affects microalgae biofilm formation and antioxidant responses. Chlorella vulgaris and Aphanizomenon flos-aquae dominate the biofilm, leading to high levels of H2O2 and O2-, while the presence of Lemna minor L. reduces oxidative stress and ROS production. Variations in the biofilm's ability to respond and produce antioxidants show that the presence of biomass of microalgae and aquatic macrophytes impacts the process of biofilm formation.