The Deconstruction of the Lignocellulolytic Structure of Sugarcane Bagasse by Laccases Improves the Production of H2 and Organic Acids.

The production of biofuels using sugarcane bagasse (SCB) as substrate can be considered an environmentally friendly approach, due to the possibility of combining energy production with the reuse of agroindustrial wastes. This study was undertaken to explore the applicability of a new extract with the enzymes (Lacmix) isolated from Chaetomium cupreum for SCB pretreatment. Lacmix was more active at pH of 2.2 to 4 and 50 to 60 °C. Further, the individual and mutual effects of SCB concentration (6.6 to 23.4 g L- 1), enzyme concentration (0.066 to 0.234 U L- 1), and incubation time of the SCB with Lacmix (19 to 221 min) on SCB pretreatment were evaluated using a response surface methodology and central composite design. The optimized conditions were 23.4 g L- 1 SCB, 0.234 U mL- 1 laccases, and 2.44 h resulting in 547 ± 108 mg L- 1 of total sugars. This value agrees with the predicted value (455 ± 41 mg L- 1) by the statistical model. Through the SCB pretreated with Lacmix fermentation, 96.1% more H2 and 22.5% more organic acids were observed compared to SCB without pretreatment. Therefore, laccases improve delignification, maximizing biomass fermentation for biofuel production.

Molecular characterization of metalloproteases from Bothrops alternatus snake venom.

We have previously demonstrated that alternagin-C (ALT-C), a disintegrin-like, Cys-rich protein isolated from Bothrops alternatus snake venom, induces human vascular endothelial cell (HUVEC) proliferation and angiogenesis in in vitro and in vivo assays. Therefore this protein could be interesting as a new approach for tissue regeneration studies. However, its primary sequence was not completely determined since the protein isolated from crude venom is usually a mixture of isoforms. Here we describe the transcriptome analysis of B. alternatus from the venom glands of a single male specimen. About 800 good-quality contigs were screened for snake venom metalloproteases/disintegrins, resulting in the following expression profile for these enzymes: 4% for P-I, 7% for P-II and 89% for P-III SVMPs. The PII-SVMP sequence code for RGD-disintegrins and all the expressed PIII-sequences have the ECD adhesive motif. A cDNA sequence coding for an ALT-C homolog was completely sequenced and characterized. Comparative sequence and structural analyses suggested new features that distinguish SVMP classes such as two prolyl endopetidase cleavage sites. All these data add new information on the expression pattern of metalloproteases of B. alternatus venom and may have practical applications for the production of recombinant disintegrins for cell adhesion studies.

Isolation of arginase inhibitors from the bioactivity-guided fractionation of Byrsonima coccolobifolia leaves and stems.

Byrsonima coccolobifolia leaf and stem extracts were studied in the search for possible leishmanicidal compounds using arginase (ARG) from Leishmania amazonensis as a molecular target. Flavonoids 1b, 1e-1g, 2a, 2b, and 2d-2f showed significant inhibitory activity, with IC50 values ranging from 0.9 to 4.8 µM. The kinetics of the most active compounds were determined. Flavonoids 1e, 1f, 2a, 2b, and 2e were characterized as noncompetitive inhibitors of ARG with dissociation constants (Ki) ranging from 0.24 to 3.8 µM, demonstrating strong affinity. Structure-activity relationship studies revealed some similarities in the structural features of flavonoids related to ARG activity.