Mixotrophic cultivation enhances lipid productivity and fatty acid profile towards efficient production of microalgae-based biofuel from Desmodesmus sp. DLK

Abstract

The selection of an appropriate strain is important for the sustainability of algae-based oil industries. In the current study, a novel omega-3 fatty acid-rich microalgal strain was isolated and identified as Desmodesmus sp. Dal Lake Kashmir (DLK) based on its morphology and molecular characterization. Its potential as biofuel feedstock was established based on its appropriate fatty acid profile and enhanced lipid productivity. The growth of Desmodesmus sp. DLK was evaluated using varying concentrations of three exogenous carbon sources (glucose, glycerol and sodium acetate) to examine the potential of the freshwater microalga to ameliorate biomass and lipid production for proficient biofuel production. A phenomenal enhancement in biomass productivity (12.8-fold) and lipid productivity (22-fold) was detected with 1% glucose in comparison to control. Supplementation with glycerol boosted the productivity of biomass and lipid maximum by 11.4-fold (5 g.L⁻¹ gly) and 26.8-fold (10 g.L⁻¹ gly), respectively. Analyses of fatty acid methyl esters from mixotrophically grown culture, via gas chromatography and mass spectrometry, exhibited a prevalence of palmitic acid (C16:0; 37%) and oleic acid (C18:1; 53%) demonstrating desirable properties for biofuel quality. This study highlights that the mixotrophic cultivation of Desmodesmus sp. DLK redirects algal metabolite fluxes towards the production of improved lipids, suitable for biofuel production.

Keywords:

• Biofuel
• carbon supplementation
• Desmodesmus
• fatty acids
• mixotrophic cultivation

Acknowledgements

The authors acknowledge financial support from the Department of Biotechnology, Ministry of Science and Technology (BT/PR6027/AGII/106/859/2012) and IOE, University of Delhi grant (2021-22). SS is thankful for an INSPIRE fellowship (IF140077) from the Department of Science and Technology New Delhi.

Author contributions

SS, DS and GM carried out the conceptual design of the study and approved the final version of the submitted manuscript; data acquisition, analyses and manuscript writing were completed by SS, with GM contributing to data interpretation and editing the manuscript critically.

Conflict of interest

The authors declare that they have no conflict of interest.

Data availability

All data generated or analysed during this study are included in this published article (and its supplementary information files). Further, the raw GC-MS data generated during and/or analysed in the current study are available from the corresponding author on reasonable request.

Ethical approval

This article does not contain any studies with human participants or animals performed by any of the authors.

Funding

This work was supported by an Inspire Fellowship, Department of Science and Technology, India; IOE-FRP Delhi University; the Department of Biotechnology, India.

Additional information

Funding

This work was supported by an Inspire Fellowship, Department of Science and Technology, India; IOE-FRP Delhi University; the Department of Biotechnology, India.