Elizama Aguiar-Oliveira and Francisco Maugeri
The lyophilization of fructosyltransferase (FTase) from Rhodotorula sp. LEB-V10 was carried out and its significant potential for synthesis of fructooligosaccharides (FOS) was evaluated and compared to the non-lyophilized enzyme. Twelve cryoprotectant additives were selected and analyzed both individually and together; the results generally showed that lyophilized enzymes have a higher enzymatic activity per gram although different levels of relative enzyme activity were observed, depending on the dilution of the initial solution. Lyophilization without additives of an enzymatic solution diluted in 1:2 (v/v) sodium acetate buffer (200 mM) pH 4.5 presented the greatest increase in enzymatic activity per gram, almost 6.5-fold higher after lyophilization and a weight reduction of almost 89%, but this result also indicated a loss of 26% of the initial enzymatic activity. Additives such as CMC at 1.25% (w/v), mannitol, ammonium sulfate, sorbitol and xylitol at 2.5% (w/v) increased enzymatic stability after 6 months from 3 to 37%. Effects of the additives alone were better than when mixed. Lyophilization also affected the biocatalytic activity of FTase, especially by increasing GF4 (% composition) by almost 3-fold.
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