Refinery of Gamma- Aminobutyric Acid (GABA) from the Fermentation of Rice Bran Extract by Ultrafiltration

Abstract

Gamma- Aminobutyric Acid (GABA) has been known as a bioactive related to the hyperglycemia, boosting the immune system, lowering blood pressure, inhabitation of development of cancer cells and assists the treatment of anxiety disorders. It has been supplied for human from germinated beans, cereal grains and tea. Recently, GABA has been also synthesized from the fermentation through the assimilation of glutamic acid by bacteria. In this paper, application of ultrafiltration (UF) for recovery of GABA from the fermentation broth of rice bran extract was investigated, with 1,000 Da of molecular weight cut off of membrane. Pretreatment of the broth by combination of centrifugation and microfiltration prior to UF improved the performance of UF process. Influence of operating pressure, in range of 2 -10 bar, was investigated and 6 bar was suitable value of operating pressure for UF of the fermentation broth. The mechanism of fouling in UF under influence of methods of pretreatment and operating pressure was also analysed, consequently, determined the flux decline model in UF. Compared to feed, content of protein in broth reduced 65 %, while, content of GABA was insignificantly changed, at 2.5 of concentration factor. Content of soluble solid, sugar and amino acid in the broth also reduced after UF process. It means that, UF process is potential technology for recovery of GABA from fermentation broth of rice bran extract.