Microalgae-based wastewater management has the potential
to serve
dual purposes, including biofuel production and wastewater bioremediation.
The current study investigates the role of 5-aminolevulinic acid (5-ALA)
in the regulation of photosynthesis, biomass accumulation, lipid production,
and nutrient removal from wastewater by Chlorella pyrenoidosa. In wastewaters, a 3 μM concentration of 5-ALA was considered
optimal, as it increased the photosynthetic light reaction and CO2 assimilation of C. pyrenoidosa cells, thereby facilitating cellular growth, metabolism, and biomass
accumulation. The acceleration of algal cellular metabolism increased
the substrate pool and enhanced the expression of lipogenic genes,
thereby promoting lipid production. Meanwhile, the removal of nutrients
from wastewater was accelerated after the addition of 5-ALA. The accelerated
nutrient removal from wastewaters following 5-ALA treatment was related
to C. pyrenoidosa cell growth. C. pyrenoidosa is capable of utilizing nitrogen and
phosphorus from wastewater and accumulating biomass. The biomass from
microalgae can be used as a feedstock to produce biofuels. Therefore,
the current study provided a novel strategy for simultaneously promoting
CO2 assimilation, biomass accumulation, lipid production,
and wastewater nutrient removal with microalgae. It is possible to
use microalgae for the management of wastewater if research and development
on commercializing technologies based on microalgae, both upstream
and downstream, are carried out continuously.