The present disclosure relates to the fields of biotechnology, molecular biology and genetic engineering. In particular, the present disclosure relates to a genetically modified alga comprising a recombinant cytochrome c6 gene, methods of producing the same and applications thereof. The present disclosure also relates to a codon optimised nucleic acid sequence encoding a cytochrome c6 polypeptide, expression cassette, vectors and host cell thereof. In an embodiment, the present disclosure also relates to a method of increasing biomass and photosynthetic efficiency of algae.
