Effects of additives on the lyophilized and thermal stability of d-galactose-6-sulfurylase activity from Eucheuma striatum (Rhodophyta).

d-galactose-6-sulfurylase has potential application in the improvement of the carrageenan quality. The lyophilized and thermal stability of the Gal-6-sulfurylase prepared from Eucheuma striatum was investigated using selected chemical additives. The addition of 5 % ( w/ v) sucrose and trehalose to Gal-6-sulfurylase prior to lyophilization could retain nearly 100 % enzymatic activity, compared to only 19 % for the lyophilized control. The lyophilized Gal-6-sulfurylase containing sucrose maintained full activity for even 40 days storage at −20 °C. For Gal-6-sulfurylase solution, glycerol was effective for long-term stability at −20 °C. Moreover, polyol sucrose and amino acid glycine enhanced the thermal stability of Gal-6-sulfurylase, while polyol mannitol decreased the thermal stability of Gal-6-sulfurylase. The results show that the Gal-6-sulfurylase, found in the red alga E. striatum, was stabilized by the addition of chemical additives. [ABSTRACT FROM AUTHOR]