Impact of H2O2 on biomass and lipid accumulation in Scenedesmus sp.: Promising species for biofuel production

Abstract

The economical production of lipids from algae needs to be investigated and optimized. Interestingly, hydrogen peroxide (H2O2) is a stress inducer that enhances lipid accumulation in microalgae. In the present study, the effect of H2O2 along with nutrients variation on total lipid accumulation in Scenedesmus sp. is investigated. Results show, H10N0P0.22 has highest lipid production (156.6 ± 24.3 μg/mg), followed by H0N0P0 (145.2 ± 33.3 μg/mg) and H10N0P0 (139.8 ± 38.1 μg/mg) after 24hrs of H2O2exposure. Gas chromatography analysis showed maximum C16:0 for H0N0P0 (24%), closely followed by H10N0P0.22 (23.4%) and H10N0P0 (23.2%) after 24hrs of H2O2 treatment, though much significant difference was not observed. Increased concentrations of H2O2 led to a decrease in biomass and “chlorophyll a” content. Biodiesel properties such as cetane number, saponification value, degree of unsaturation and Iodine value have also been observed in the current study to understand the impact of combined stress. Further principal component analysis (PCA) amongst various combinations reveals that H10N0P0.22 is a significant contributor to the variance. Thus, Scenedesmus sp. under oxidative stress yield increased accumulation of total lipid with less significant difference after 24 h of H2O2 treatment, thus, this study can be further examined under the various optimized condition to be utilized in large-scale cultivation of biodiesel targeting the ever-increasing energy demands.