Efecto de los parámetros operacionales y las condiciones de cultivo en la valorización de microalgas mediante hidrólisis enzimática

Abstract

This work studies the effect of operating conditions on the solubilization of the main macromolecular compounds contained in algal biomass (proteins, carbohydrates and lipids) by enzymatic hydrolysis. The study proposes the valuation of biomass based on the microalgae Scenedesmus almeriensis, a microalgae species with a very resistant cell wall which is often used for the treatment of wastewater on photobioreactors. In this type of bioreactors, microalgae and bacteria grow symbiotically, forming consortia; bacteria use the O2 generated by the microalgae to degrade organic matter, generating CO2 and other compounds used by the microalgae for their growth. The presence of bacteria in the biomass generated in these treatment plants can considerably affect subsequent recovery processes. Thus, in this work, the results of the valorization are compared, using enzymatic hydrolysis of mixed biomass of microalgae and bacteria grown in pig slurry (A1 biomass) and pure microalgae grown in synthetic medium (A2 biomass). The operational factors studied were type of enzyme (Alcalase, Protamex and Celluclast) and hydrolysis time (1, 3 and 5 h). Although the extraction of both proteins and carbohydrates and lipids is being studied, this work is oriented towards the extraction of proteins, the majority component of the biomass under study. The two types of biomass (A1 and A2) were subjected to enzymatic hydrolysis combining the levels of the two control factors, resulting in a total of 18 different experiments. The analysis of the residual biomass of each experiment showed a total solubilization with values between 16 and 26 %, depending on the experimental conditions. Of the total solubilized mass, proteins represented between 9 and 55% and carbohydrates between 16 and 37%. The analysis of variance (ANOVA) of the results indicated that the most influential factors are biomass and type of enzyme used, achieving protein solubilizations with the use of the enzyme Alcalase of between 26 and 55% and with the use of the A2 microalgae biomass between 13 and 55%.