초록
<P><B>Abstract</B></P> <P>Microalgal biomass is considered as a propitious feedstock for bioenergy generation. The present research work aimed to maximize the biomass and carbohydrate productivity of <I>Scenedesmus obliquus</I> UTEX 393 by optimizing physico-chemical parameters using single and multi-parameter optimization strategies. Individual and interactive effects of different parameters (temperature, pH, carbon source concentration and nitrogen source concentration) were investigated. Multi-response optimization study resulted in maximum biomass and carbohydrate productivity of 491 mg L<SUP>−1</SUP> d<SUP>−1</SUP>and 270 mg L<SUP>−1</SUP> d<SUP>−1</SUP>, respectively at the initial pH 6.69, temperature 27.65 °C, glucose concentration 3.33 g L<SUP>−1</SUP> and urea concentration 126.77 mg L<SUP>−1</SUP>. Effect of photobioreactor configuration on biomass and carbohydrate production was also investigated. The biomass and carbohydrate productivity were enhanced to 560 mg L<SUP>−1</SUP>d<SUP>−1</SUP> and 309 mg L<SUP>−1</SUP> d<SUP>−1</SUP>, respectively using airlift photobioreactor. In a biorefinery framework, before subjecting the biomass for fermentative biohydrogen production, the lipid present (22.6% w/w) in the microalgae was extracted and transesterified for biodiesel production. The potentiality of defatted microalgal biomass (rich in carbohydrate) as a substrate for the dark fermentation process was evaluated using acidogenic mixed consortia. Cumulative hydrogen production of 68.9 mL g<SUP>−1</SUP> DCW was achieved, which suggested the suitability of deoiled algal biomass as a biohydrogen feedstock.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Maximization of biomass and carbohydrate productivity using <I>S. obliquus</I>. </LI> <LI> 55.4% w/w carbohydrate content was obtained under optimized conditions. </LI> <LI> FAME analysis revealed 81.79% relative abundance of C<SUB>16</SUB>–C<SUB>18</SUB> fatty acids. </LI> <LI> H<SUB>2</SUB> yield of 68.9 mL g<SUP>−1</SUP> DW was achieved using de-oiled algal biomass as feedstock. </LI> </UL> </P>