Abstract:
Due to rapid urbanization, population explosion and widespread industrialization, the
twin problems of energy security and global warming are gaining momentum as
dependency on fossil fuels continues. Increased greenhouse gas emissions along with
release of untreated wastewater from different sectors pose a serious threat to
sustainable environment. As the global search for solutions to these problems
continues, wastewater treatment by microalgae is an attractive option which achieves
two goals simultaneously: Phyto-remediation and biomass as a feedstock for biofuel
production. Furthermore, many algal species have the ability to generate hydrogen
gas in anaerobic mode due to the presence of hydrogenase enzyme. This process is
an electron dependent reaction which commences upon the photolytic splitting of
water molecules which releases electrons and protons in photosystems of algal
chloroplasts. In the absence of oxygen, these electrons are transported to
hydrogenase that reduces protons and generates renewable fuel hydrogen gas. Using
this background knowledge, this study is designed to explore the hydrogen
production and wastewater phytoremediation ability of local algae strains. The local
algal strains were first isolated and preserved, then cultivated aerobically under
ambient conditions in synthetic growth medium (BBM) till exponential growth
phase. Afterwards, these strains were exposed to anaerobic conditions for the
maximum transfer of electrons towards hydrogenase to determine hydrogen
potential. Afterwards, as another research objective, local algae strains were
subjected to cultivation in institutional and textile wastewater samples acquired to
determine their phtyoremediation ability along with hydrogen gas potential. Results
showed all strains having hydrogen generation ability and good removal efficiency of
major nutrients (phosphates, sulfates, nitrates), BOD and COD from wastewater,
thereby improving overall water quality. In addition, algal biomass was harvested
and used for lipid extraction and determining other biofuel potential via FTIR
analysis. Hence this study reflects an environmentally safe alternative for treating
wastewater which is not only cost effective, but also yields far better results in
reducing water pollution and providing potential sources of biofuel.