Comprehensive characterization of microalgal isolates and lipid-extracted biomass as zero-waste bioenergy feedstock: An integrated bioremediation and biorefinery approach.

Graphical abstract Highlights • Monoraphidium sp. KMC4 found to be novel strain among eight other DSW isolates. • Biochemical, CHNS, TGA, FTIR validated KMC4′s potential as bioenergy feedstock. • FAME with 78% of C16/C18 confirmed the feasibility of biodiesel production. • LEMB characterization also suggested it as a high-value bioenergy feedstock. • Optimal biomass to energy conversion validated zero-waste biorefinery approach. Abstract The present study investigated the feasibility of domestic sewage wastewater (DSW) as an alternate to fresh-water microalgae growth media towards high-value bioenergy feedstock production. Eight native microalgal strains were screened from DSW and the effect of raw DSW (RDSW), and autoclaved DSW (ADSW) on growth and bioremediation potential were evaluated and compared with control BG11 medium. The study confirmed RDSW as a potential growth medium while Monoraphidium sp. KMC4 showed superior biomass (1.47 ± 0.08 g L−1) and lipid yield (436.01 ± 0.06 mg L−1). The corresponding values for bioremediation of ammonia, nitrate, phosphate, as well as COD remained within 88–100%. CHNS, biochemical, TGA, FTIR, FAME analysis of KMC4 confirmed it's potential as bioenergy feedstock. Additionally, a comprehensive characterization of lipid-extracted microalgae biomass (LEMB) was carried out which suggested that LEMB can be used as a growth promoter as well as feedstock for biogas, bioethanol, and bio-oil production. [ABSTRACT FROM AUTHOR]