초록
<P><B>Abstract</B></P> <P>The integrated system of astaxanthin and microalgal biomass production, and wastewater treatment is a promising process. <I>Haematococcus pluvialis</I> is a suitable microalgae for this coupled system to achieve this dual purpose in a single approach. In this study, biomass production and nutrient removal from bioethanol plant wastewater by <I>H. pluvialis</I> were investigated. An air-lift photobioreactor was used to utilize the wastewater as well as a CO<SUB>2</SUB>-enriched gas supply. The maximum biomass density and maximum specific growth rate achieved were 4.37±0.007g/L and 0.317day<SUP>−1</SUP>, respectively, by culturing <I>H. pluvialis</I> in an air-lift photobioreactor, supplemented with 5% CO<SUB>2</SUB> in air. Removal of 91.7% total nitrogen and 100% total phosphorous from the wastewater was achieved. The residual microalgal biomass, obtained after astaxanthin extraction (1.109±0.009mg/g DW), was characterized as a potential bioenergy feedstock due to its elevated higher heating value 15.6±0.01MJ/kg. Hence, integrating <I>H. pluvialis</I> cultivation with bioethanol effluent serves the combined purpose of wastewater treatment, CO<SUB>2</SUB> utilization, and simultaneous production of astaxanthin, which has a potential market value of over USD 2000perkg, and carbohydrate rich microalgal biomass, which can be applied to bioenergy production.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Enhanced microalgal biomass production was achieved using air-lift photobioreactor. </LI> <LI> 5% CO<SUB>2</SUB> supplementation resulted in maximum biomass density and specific growth rate. </LI> <LI> Wastewater made environmentally safe with 91.67% TN and 100% TP removal. </LI> <LI> Astaxanthin-extracted <I>H. pluvialis</I> biomass is a potential bioenergy feedstock. </LI> <LI> Integrated <I>H. pluvialis</I> cultivation-ethanol production is economically beneficial. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>