Enzymatically and/or thermally treated Macroalgae biomass as feedstock for fermentative H2 production

Abstract

Due to its high carbohydrate content, algae biomass can be employed as feedstock to produce hydrogen (H2)
by fermentation. However, to make the carbohydrates entrapped within the cell wall more bioavailable, algae
biomass must be treated before fermentation. We submitted Kappaphyccus alvarezzi macroalgae biomass to
autoclave (at 120 °C and 1 atm for 6 h) treatment and/or enzymatic (Celluclast® and/or a recombinant β-
glucosidase) hydrolysis, to break down complex carbohydrates into available sugars that were used to produce
H2 by fermentation. Macroalgae biomass treated with Celluclast®+β-glucosidase and with combined
thermal treatment and enzymatic hydrolysis reached very similar TRS productivities, 0.24 and 0.22 g of
TRS/L.h, respectively. The enzymatically treated biomass was employed as feedstock to produce H2 by
Clostridium beijerinckii Br21, which afforded high yield: 21.3 mmol of H2/g of dry algae biomass. Hence,
treatment with Celluclast® and recombinant β-glucosidase provided macroalgae biomass for enhanced bioconversion
to H2 by C. beijerinckii Br21.
Keywords: Kappaphyccus alvarezzi, Clostridium beijerinckii, Biohydrogen, Cellulase, β-glucosidase