ACTIVITY AND PRIMARY CHARACTERIZATION OF ENZYME FROM THERMUS RUBER CELLS CATALYZING CONVERSION OF MALTOSE INTO TREHALOSE

Thermophilic bacteria Thermus ruber produces enzyme, which catalyzes the conversion of maltose into trehalose. The specific activity of the cell-free extract from this bacteria growing without inducers was 0.028 U/mg protein and it was increased to up to 0.086 U/mg in the presence of 0.5% of maltose in the culture broth. The maximum degree of maltose conversion of about 90% was attained at 10% substrate concentration. The enzyme from Thermus ruber does not catalyze formation of trehalose from maltotetraose and maltopentaose. The optimum temperature for the enzyme activity was 65C. A maximum activity of the maltose conversion was performed at pH 6.5. The highest enzyme activity was achieved during cell cultivation at 55C on a media composed from 0.5% of peptone, 0.1% yeast extract and 0.5% of maltose or starch. Trehalose is a chemically stable nonreducing disaccharide which can be used in food, cosmetics, medical and biotechnological industries. Extraction of this carbohydrate from yeast cells or other natural sources is unsuitable for trehalose production because of low process yield and high cost. Thus, the enzymatic methods of trehalose production are developed. In the current study the thermophilic bacteria Thermus ruber has been examined as a new source of the enzyme catalyzing conversion of maltose into trehalose.