Co-digestion of untreated macro and microalgal biomass for biohydrogen production: Impact of inoculum augmentation and microbial insights

다국어 초록 (Multilingual Abstract)

<P><B>Abstract</B></P> <P>This study assessed the co-digestion of macro and microalgal biomass towards the improvement of hydrogen production. The red macroalgal biomass (<I>Gelidium amansii</I>) and green mixed microalgal biomass was mixed in a ratio of 8:2, with an initial substrate concentration of 10 g/L, and various amount of inoculum addition range from 3 to 15% (v/v) was evaluated to assess the feasible substrate to inoculum ratio for the effective co-digestion of the algal biomass. The results showed that the co-digestion with 6% inoculum addition provided the peak hydrogen yield of 45 mL/g dry biomass added with a high hydrogen content of 24% in the gas phase. The other tested conditions showed moderate hydrogen content in the range of 17–22%, respectively. These results suggest that anaerobic co-digestion of macro and microalgal biomass, with appropriate initial biomass loading (6%) is essential for enhanced hydrogen production.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Inoculum augmentation improves the co-digestion performances. </LI> <LI> Maximum hydrogen yield of 45 mL H<SUB>2</SUB>/g TS was achieved. </LI> <LI> Peak COD removal efficiency of 28.5% achieved at 6% inoculum loading rate. </LI> <LI> <I>Eubacteria</I> and <I>Clostridium</I> were the dominant microflora. </LI> </UL> </P>