RESUMO
A new alternative for hydrodynamic cavitation-assisted pretreatment of sugarcane bagasse was proposed, along with a simultaneous saccharification and co-fermentation (SSCF) process performed in interconnected columns. Influential variables in the pretreatment were evaluated using a statistical design, indicating that an ozone flow rate of 10 mg min-1 and a pH of 5.10 resulted in 86 % and 72 % glucan and xylan hydrolysis yields, respectively, in the subsequent enzymatic hydrolysis process. Under these optimized conditions, iron sulfate (15 mg L-1) was added to assess Fenton pretreatment, resulting in glucan and xylan hydrolysis yields of 92 % and 71 %, respectively, in a material pretreated for 10 min. In SSCF, ethanol volumetric productivities of 0.33 g L-1 h-1 and of 0.54 g L-1 h-1 were obtained in batch and fed-batch operation modes, achieving 26 g L-1 of ethanol in 48 h in the latter mode.
Assuntos
Celulose , Saccharomycetales , Saccharum , Celulose/metabolismo , Fermentação , Saccharum/metabolismo , Etanol , Hidrodinâmica , Células Imobilizadas/metabolismo , Xilanos , HidróliseRESUMO
The effect of a non-ionic surfactant optimized formulation (SOF) obtained from an experimental design was evaluated for different influencing variables in the processing of sugarcane bagasse cellulignin to produce biopigments. The major findings in the saccharification stage using the SOF point that: at same enzyme loading, the highest glucan hydrolysis yield was 63 % (2-fold higher compared to control); the enzyme loading of 2.5 FPU/g resulted in similar yield compared to 10 FPU/g (control); 15 % (m/v) of total solids loading maintained the yield in fed-batch configuration; the hydrolysis yield is maintained at high shear force stress (800 rpm of stirring rate) and temperatures (50-70 °C). Besides, under separate and semi-simultaneous hydrolysis and fermentation, the maximum biopigments production were of 10 AU510nm/mL and 17.84 AU510nm/mL, respectively. The SOF used in this study was found to be a promising additive either in a single or sequential steps to produce biopigments in biorefineries.
Assuntos
Saccharum , Celulose/metabolismo , Fermentação , Hidrólise , Monascus , Saccharum/metabolismo , TensoativosRESUMO
Environmental problems due to utilization of fossil-derived materials for energy and chemical generation has prompted the use of renewable alternative sources, such as lignocellulose biomass (LB). Indeed, the production of biomolecules and biofuels from LB is among the most important current research topics aiming to development a sustainable bioeconomy. Yet, the industrial use of LB is limited by the recalcitrance of biomass, which impairs the hydrolysis of the carbohydrate fractions. Hydrodynamic cavitation (HC) and Advanced Oxidative Processes (AOPs) has been proposed as innovative pretreatment strategies aiming to reduce process time and chemical inputs. Therefore, the underlying mechanisms, procedural strategies, influence on biomass structure, and research gaps were critically discussed in this review. The performed discussion can contribute to future developments, giving a wide overview of the main involved aspects.
Assuntos
Hidrodinâmica , Lignina , Biocombustíveis , Biomassa , Lignina/metabolismo , Estresse OxidativoRESUMO
L-asparaginase is an important enzyme used in the pharmaceutical and food industry, which can be produced by different microorganisms using low cost feedstocks. In this work, sugarcane bagasse (SCB) was used as support for enzyme production in solid-state fermentation (SSF) by A. terreus. Initially, the influence of the variables carbon and nitrogen sources on the enzyme production was studied following an experimental design carried out in Erlenmeyer flasks. Statistical analysis indicated the use of 0.54% of starch, 0% of maltose, 0.44% of asparagine, and 1.14% of glutamine in the medium, resulting in enzyme activity per volume of produced extract of 120.723 U/L. Then, these conditions were applied in a horizontal column reactor filled with SCB, producing 105.3 U/L of enzyme activity. Therefore, the potential of extracellular L-asparaginase enzyme production in the column reactor using sugarcane bagasse as support was demonstrated and it represents a system that can favor large scale production.