Volatile fatty acid-treated mixotrophic cultivation of lipid/carbohydrate-rich cyanobacterial species, Pseudanabaena mucicola GO0704, for the enhancement of biofuel production.

[Display omitted] • Mixotrophic culture of cyanobacteria using volatile fatty acid (VFA) was conducted. • Butyric acid and acetic acid treatment increased the growth of Pseudanabaena mucicola. • VFA-based mixotrophic culture did not affect biochemical composition of P. mucicola. • Butyric acid treatment enhanced the production of biodiesel and bioethanol more than 2-folds. • Biodiesel produced from butyric acid treatment meets the standard fuel property. Cyanobacteria-derived biofuels can be helpful in achieving a circular bioeconomy. To increase the production of biodiesel/bioethanol from cyanobacterium, Pseudanabaena mucicola GO0704, mixotrophic cultivation using volatile fatty acid (VFA), a cheap organic carbon source, was performed. The treatment of butyric acid or acetic acid enhanced the cell growth, particularly, the dry weight of the butyric acid-treated cells was 2.30-fold higher than the control. The enhancement of the growth led to the increase of metabolite (i.e., lipid and carbohydrate) productions, resulting in high amount of biodiesel and bioethanol to be produced. Butyric acid was more effective compared to acetic acid and the productions of biodiesel (52.2 mg/L) and bioethanol (132.6 mg/L) from the butyric acid-treated P. mucicola GO0704 were 2.34- and 2.17-fold higher compared to the control, respectively. This study will provide a foundation to commercialize the cyanobacteria-based carbon–neutral fuels, and ultimately, achieve a circular bioeconomy. [ABSTRACT FROM AUTHOR]