Strategy for biotechnological process design applied to the enzymatic hydrolysis of agave fructo-oligosaccharides to obtain fructose-rich syrups.García-Aguirre M, Sáenz-Alvaro VA, Rodríguez-Soto MA, Vicente-Magueyal FJ, Botello-Alvarez E, Jimenez-Islas H, Cárdenas-Manríquez M, Rico-Martínez R, Navarrete-Bolaños JL.
Departamento de IngenieriaQuimica-Bioquimica, Instituto Tecnologico de Celaya, Avenida Tecnologico s/n, C.P. 38010, Celaya, Guanajuato, Mexico.
A strategy to optimize biotechnological process design is illustratedfor the production of fructose-rich syrups via enzymatic hydrolysis of agave fructo-oligosaccharides. The optimization process includes ecological studies from natural fermentations leading to theselection of a strain with capacity for inulinase synthesis, and variable optimization for the synthesis, and enzymatic hydrolysis using the response surface methodology. The results lead to theselection of Kluyveromyces marxianus , endogenous strains isolated from aguamiel (natural fermented sugary sap from agave plants), as the main strain with high capacity for enzyme synthesis with inulinaseactivity. Production optimization at bioreactor level revealed that operation at 30.6 degrees C, 152 rpm, 1.3 VVM of aeration, and pH 6.3 leads to maximum inulinase synthesis, whereas 31 degrees C,50 rpm, and pH 6.2 leads to maximum hydrolysis of agave fructo-oligosaccharides. HPLC analysis of the fructose-rich syrups obtained at these optimal conditions showed an average composition of 95% offructose and 5% of glucose and the absence of sucrose. The analysis also revealed that the syrups are free of residues and toxic compounds, an undesirable occurrence often present when traditionalmethods based on thermal or acid hydrolysis are applied for their obtainment. Therefore, the product may be suitable for use as additive in many applications in the food and beverage industries.