Otimização da hidrólise ácida da macroalga vermelha Solieria filiformis visando a geração de alto teor de monossacarídeos totais

Abstract

With the Industrial revolution, the use of fossil resources made possible to reach better production efficiencies and to create new products, permanently redefining the society. However, this resources are limited and its use caused and still causing environmental problems due to CO2 emission. In this scenario, biomass emerge as a renewable and advantageous material owing natural characteristics and high availability, to be used in chemical and renewable fuels production; among all biomass, seaweeds present characteristics that allows its application, as less recalcitrant structure when compared with terrestrial biomass. In this context, this work aimed to acid hydrolysis of red seaweed Solieria filiformis Central composite design (CCD) and Response surface methodology (RSM) to generate a high sugar concentration medium contend. The design elaborated with Statistica version 10.0 with 17 independent experiments of hydrolysis to study 3 parameters (sulfuric acid concentration, biomass load concentration and time of reaction); were analyzed 4 response variables (total sugar generation, biomass to sugar conversion yield (Y_(M⁄B)), Total galactose generation and recovered hydrolysis liquid). The seaweeds were harvested in farming structures located in Flecheiras’ Beach, Trairi, Ceará, washed, dried at 25 °C and crushed in electric mill. Hydrolysis were conducted in autoclave at 120 °C with different acid concentration, biomass load and time of process for each experiment. The results obtained were analyzed by analysis of variance (ANOVA). The influence of each parameter over the responses was studied. Mathematical models, response surface plots or contour plots were created for each once on the responses. After, Total sugar and galactose were optimized and kinetic hydrolysis plots were created for each once on the parameters using the responses. To response Total sugar and galactose, the quadratic parameter of acid concentration and the linear and quadratic parameter of quantity of biomass were significant. For the response Y_(M⁄B), the quadratic parameter of acid concentration and the linear parameter of loading of biomass were significant. To response Total galactose, the quadratic parameter of acid concentration and the linear and quadratic parameter of quantity of biomass were significant. For the response Recovered liquid, the linear and quadratic parameters of concentration of acid and the linear parameter of loading of biomass were significant. The linear and quadratic parameters of hydrolysis time and the interactions between parameters were not significant for any of the studied responses. Mathematical models were created for the three responses, Total sugar, Y_(M⁄B), Total galactose and Recovered liquid, with R2values of 0.88, 0.8, 0.89 and 0,8, respectively for p = 0.05. The optimization of Total sugar generated in silico results of 174.06 g.L-1 of total sugars for using parameters of 1.8 M sulfuric acid, 723.3 g,L-1 of biomass and 36.8 min of reation. The optimization of Total galactose generated in silico results of 154.74 g.L-1 of total sugars for using parameters of 1.6 M sulfuric acid, 665.7 g,L-1 of biomass and 32.9 min of reaction. The simulation of Y_(M⁄B) and recovered liquid to the optimum parameters generated 0.2515 and 89%, respectively. Thus, it is concluded that it was possible to optimize the acid hydrolysis of S. filiformis to the production of high amount of total sugar and glactose with knowledge of the Y_(M⁄B) and recovered liquid, generating a predictive mathematical modeling with statistical confidence for the three answers.