Abstract

Trehalose has similar chemical formula as maltose. In terms of price, trehalose is much more expensive than maltose. A pink-pigmented bacterium identified asMeiothermus sp. SK3-2 was found to be able to convert maltose to trehalose. Based on fatty acids analysis, the Meiothermus sp. SK3-2 may be a new strain that produce trehalose synthase (TreS). Meiothermus sp. SK3-2 achieved a better biomass growth in MM medium containing maltose. Besides that, TreS activity yield was also higher in MM medium, approximately 3.5, 1.8 and 0.3 fold than that in PY medium, thermophilic Bacillus medium and Castenholz medium, respectively. The optimum working temperature and pH for Meiothermus sp. SK3-2 TreS was 65°C and pH 6.0, respectively. Ammonium chloride at 10 mM increased the activity significantly, while calcium chloride at 5 mM decreased the activity by about 80% and the activity was fully retarded by 10 mM CaCl₂. It was found that the product specificity of this TreS was influenced by factors like temperature, pH and buffer system used. Analysis of the nucleotide sequence revealed the presence of an open reading frame of 2,890 bp which encoded a 963 amino acid protein. In conclusion, Meiothermus sp. SK3-2 TreS could serve as an alternative source to trehalose production.

Key words: Maltose, Meiothermus, trehalose, trehalose synthase.

Abbreviation

GPase, a-1,4-D-Glucan phosphorylase; MTHase, maltooligosyl trehalose trehalohydrolase; MTSase, maltooligosyl trehalose synthase; PCR,polymerase chain reaction; TreS, trehalose synthase; TPase, trehalose phosphorylase; T_opt., optimum temperature.