Production of a thermo-tolerant kappa-carrageenase via a food-grade host and anti-oxidant activity of its enzymatic hydrolysate

Abstract

kappa-Carrageenase cleaves the beta-(1-4) linkages of kappa-carrageenan into kappa-carrageenan oligosaccharides (kappa-COS), which exhibit various biological activities. In this study, a glycoside hydrolase (GH) family 16 kappa-carrageenase gene, cgkA, was cloned from the marine bacterium Vibrio sp. SY01 and secretory expressed in a food-grade host, Yarrowia lipolytica. The specific activity of the purified CgkA was 12.5 U/mg. Determination of biochemical properties showed that CgkA was a thermo-tolerant enzyme, and 59.9% of the initial enzyme activity was recovered by immediately placing the sample at 20 degrees C for 30 min after enzymatic inactivation by boiling for 5 min. The recombinant CgkA was an endo-type enzyme, the main enzymatic product was kappa-carradiaose (accounting for 87.6% of total products), and kappa-carratetraose was the minimum substrate. Additionally, in vitro and in vivo analyses indicated that enzymatic kappa-carradiaose possesses anti-oxidant activity. These features make CgkA as a promising candidate for biotechnological applications in the production of anti-oxidant kappa-COS.