Abstract We report on the nearly complete genome sequence of Clostridium beijerinckii strain Br21, formerly isolated from a sugarcarne vinasse wastewater treatment plant. The resulting genome is ca. 5.9 Mbp in length and resembles the size of previously published C. beijerinckii genomes. We annotated the genome sequence and predicted a total of 5323 genes. Strain Br21 has a genetic toolkit that allows it to exploit diverse sugars that are often found after lignocellulosic biomass pretreatment to yield products of commercial interest. Besides the whole set of genes encoding for enzymes underlying hydrogen production, the genome of the new strain includes genes that enable carbon sources conversion into butanol, ethanol, acetic acid, butyric acid, and the chemical block 1,3-propanediol, which is used to obtain polymers. Moreover, the genome of strain Br21 has a higher number of ORFs with predicted beta-glucosidase activity as compared to other C. beijerinckii strains described in the KEGG database. These characteristics make C. beijerinckii strain Br21 a remarkable candidate for direct use in biotechnological processes and attest that it is a potential biocatalyst supplier.

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.