Performance evaluation of genetically modified microalgae in photosynthetic microbial fuel cells for carotenoids and power generation

The photosynthetic microbial fuel cells (PMFCs) have showcased considerable potential for sustainable bioenergy and bioproduct generation while cultivating microalgae in the cathode chamber. Nevertheless, the exploration of genetically engineered microalgae as cathodic species in PMFCs is currently limited. This study systematically compares the performance of wild type (WT) and genetically modified (GM) Chlamydomonas reinhardtii in PMFCs, focusing on bioelectricity and bioproduct generation. The study showed that β-carotene productivity in MFCs with WT and GM strains has reached 1.55 ± 0.05 and 3.88 ± 0.14 mg/g DCW, respectively. Therefore, the MFC cathode environment significantly boosted the β-carotene production (2.49-fold) in microalgae compared to flask-grown cultures. Moreover, power generation in MFCs using GM strains (0.99 ± 0.15 W/m3) was not significantly different from that of WT species (1.26 ± 0.27 W/m3). The removal of anodic chemical oxygen demand (COD) reaches up to 79 % in MFCs with GM microalgae. Therefore, the current investigation presents a proof of concept for GM microalgae-based PMFCs, which may strengthen the existing bioproduct synthesis at a global scale by enhancing microalgae growth and carotenoid production.