STUDY OF PRE-TREATMENT AND ENZYMATIC SACCHARIFICATION OF MICROALGAL BIOMASS FOR BIOETHANOL PRODUCTION
Due to the growing demand for renewable fuel sources, microalgae have been attracting global interest as an alternative to the production of biofuels such as bioethanol. The production of bioethanol by microalgae is limited and depends on the steps of pretreatment necessary in the conversion of complex carbon molecules to simple sugars before the fermentation process. The objective of this study was to evaluate cell rupture methods to release the carbohydrates present in Spirulina platensis for later saccharification. The methods used were ultrasonic probe, heat treatment and freezing-thawing. The evaluation of the efficiency of these methods was carried out by determining the reducing sugars released after the saccharification of 10% (w/v) biomass solution in sodium phosphate buffer pH 5.5 at 50°C in a shaker table at 150 rpm, using amilolytic enzymes diluted 200-fold. Saccharification was evaluated in a 20% (w/v) solution in sodium phosphate buffer pH 5.5 at 50°C for 12 hours, using undiluted amylolytic enzymes. It was observed that the highest concentration of reducing sugars was obtained in the pre-treatment of freezing and thawing, resulting in 7.5 and 15.25 g/L of reducing sugars formed after 1 and 2 hours of hydrolysis respectively. Saccharification showed efficiency of approximately 75%.