Abstract

MEDIUM OLEIC SUNFLOWER OIL HYDROLYSIS BY MICROBIAL LIPASE IN A FED-BATCH BIOREACTOR

Sylvio Jorge Hares Júnior, Juliana Neves Rodrigues Ract, Luiz Antonio Gioielli, Michele Vitolo*

ABSTRACT

Mono- and diacylglycerols are used in the food and cosmetic industries as emulsifiers and viscosity controllers. This work addresses hydrolysis of medium oleic sunflower oil by immobilized lipase to obtain monoacylglycerols and diacylglycerols using a bioreactor operated with a fed-batch regimen. The oil was added into the bioreactor according to a constant feeding mode. The volume inside the bioreactor varied from 100 mL to 300 mL. The filling time and the adding time interval changed from 2.6 h to 5.4 h and from 0.1 h to 2.9 h, respectively. The amount of immobilized lipase (10% w/w), temperature (50oC), pH (7.4) and agitation (180 rpm) were kept constant. The assays were designed according to the response surface methodology. The raw material (medium oleic sunflower oil), the standards (triolein, monolein, diolein, and oleic acid) and the hydrolyzed products were analyzed using acidity test (degree of hydrolysis), thin layer chromatography (TLC) and high-pressure size exclusion chromatography (HPSEC). The maximum formation of monoacylglycerols and diacylglycerols occurred at substrate filling time and adding interval of 4-5 h and 0.1-0.5 h, respectively. The percent of mono- and diacylglycerols obtained by hydrolysis varied from 8-10% to 27-32%, respectively.

Keywords: Monoacylglycerol, diacylglycerol, monolein, diolein, medium oleic sunflower oil.