OPTIMIZATION OF FERMENTATION OF Ulva SP. HYDROLYSATE BY NOVEL YEAST Cyberlindnera jadinii MMS7 FOR ENHANCEMENT OF POLYPHENOL CONTENT AND ANTIOXIDANT ACTIVITY

Abstract

This study is aimed to evaluate the total phenols (TP) content and antioxidant activity of green alga Ulva sp. hydrolysate by aerobic fermentation using novel yeast Cyberlindnera jadinii  MMS7. Response surface methodology (RSM) was applied to optimize the ultrasound assisted hydrolysate preparation from Ulva sp and found that the ultrasound power density of 0.35 WmL^-1 at 15 min as optimum for hydrolysate preparation by ultrasonic pretreatment. The maximum TP of 35.75 ± 0.12 mg PGE g^-1 observed in these condition, hence, it was used for further investigation for enhancing the TP content of hydrolysate. By the classical method of optimization pH 5.5, temperature 35^oC and agitation speed 150 rpm were found to be the optimum physical parameters for improving TP content (44.59±0.06 mg PGE g^-1) of Ulva sp. hydrolysate fermentation by C .jadinii MMS7. At these optimum conditions, 3.26 fold DPPH radical scavenging activity was observed in fermented extract than unfermented extract. Therefore, this study demonstrates that the RSM is an adequate approach for optimization of ultrasound assisted hydrolysate preparation from Ulva sp. In addition to this, the novel yeast strain C. jadinii MMS7 considered as potential candidate for fermentation of Ulva sp. hydrolysate for enhanceing TP content and antioxidant activity.

Keywords:  Antioxidant activity, Cyberlindnera jadinii, fermentation, hydrolysate, RSM, total phenols, Ulva sp.