Comparativa de valorización de la fracción carbohidrato de diferentes biomasas microalgales aplicando técnicas de diseño de experimentos

Un mismo diseño de experimentos de Taguchi L27 permitió estudiar las etapas de pretratamiento y de hidrólisis enzimática de diferentes biomasas microalgales (procedente de plantas de tratamiento de purines, de aguas residuales y pura) en términos de liberación y recuperación de azúcares; pero también de liberación de proteínas y lípidos. Los pretratamientos estudiados fueron ácido y básico diluido. El máximo rendimiento de azúcar recuperado fue 91.20% para el alga pura aplicando HCl 2 M a 121°C durante 10 minutos y una concentración de alga de 75 g/L, con una concentración de enzima de 10 FPU durante 3h. El pretratamiento ácido favoreció la liberación y recuperación de azúcares, mientras que el básico incrementó la liberación de proteínas y lípidos. El factor más significativo, independientemente del tipo de alga empleada, resultó la temperatura de pretratamiento, seguido de la concentración del agente químico, con los mejores resultados a 121ºC y concentración 2 M.Departamento de Ingeniería Química y Tecnología del Medio AmbienteGrado en Ingeniería Químic

Optimisation of the production of fermentable monosaccharides from algal biomass grown in photobioreactors treating wastewater

Producción CientíficaBiomass grown in wastewater treatment photobioreactors is a cheap raw material with high contents of carbohydrates, proteins and lipids. This work studies the production of fermentable monosaccharides from three biomasses grown in piggery wastewater (P), domestic wastewater (W) and synthetic medium (S) by applying chemical pretreatment and enzymatic hydrolysis, using a Taguchi design. ANOVA identified temperature, chemical reagent type and chemical reagent concentration as significant operational parameters. However, the biomass concentration, pretreatment time, enzyme dosage and enzymatic hydrolysis time had no remarkable effect. The bacterial content of the biomass had no relevant impact on carbohydrate and protein solubilisation but had a remarkable effect on the degradation of the released carbohydrates (57, 60 and 37% for P, W and S), while also affecting lipid solubilisation. Pretreatment with HCl 2 M at 120 °C resulted the optimal conditions, achieving a monosaccharide recovery of 53, 59 and 80% for P, W and S biomasses, respectively.Gobierno regional de Castilla y León (UIC 071, CLU 2017-09 and VA080G18)Ministerio de Ciencia, Innovación y Universidades (project CTQ2017-84006-C3-1-R)Unión Europea - FEDER (CLU 2017-09 and CTQ2017-84006-C3-1-R

Effect of pretreatments on biogas production from microalgae biomass grown in pig manure treatment plants

Methane production from pretreated and raw mixed microalgae biomass grown in pig manure was evaluated. Acid and basic pretreatments provided the highest volatile solids solubilisation (up to 81%) followed by alkaline-peroxide and ultrasounds (23%). Bead milling and steam explosion remarkably increased the methane production rate, although the highest yield (377 mL CH4/g SV) was achieved by alkali pretreatment. Nevertheless, some pretreatments inhibited biogas production and resulted in lag phases of 7-9 days. Hence, experiments using only the pretreated solid phase were performed, which resulted in a decrease in the lag phase to 2-3 days for the alkali pretreatment and slightly increased biomass biodegradability of few samples. The limiting step during the BMP test (hydrolysis or microbial inhibition) for each pretreatment was elucidated using the goodness of fitting to a first order or a Gompertz model. Finally, the use of digestate as biofertilizer was evaluated applying a biorefinery concept.Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria – INIA”, “Ministerio de Economía y Competitividad – MINECO (RTA2013-00056-C03-02) supported by FEDER program,Junta de Castilla y León – JCyL (VA094U14)Junta de Castilla y León – JCyL Doctorate Scholarship