Purification and characterization of a thermostable λ-carrageenase from a hot spring bacterium, Bacillus sp.

Purpose of work The purpose of this study is to report a thermostable λ-carrageenase that can degrade λ-carrageenan yielding neo-λ-carrabiose at 75 °C.A thermophilic strain Lc50-1 producing λ-carrageenase was isolated from a hot spring in Indonesia and identified as a Bacillus sp. The λ-carrageenase, Cga-L50, with an apparent molecular weight of 37 kDa and a specific activity of 105 U/mg was purified from the culture supernatant. The optimum pH and temperature of Cga-L50 were 8.0 and 75 °C, respectively. The enzyme was stable from pH 6-9 and retained ~50 % activity after holding at 85 °C for 10 min. Significant activation of Cga-L50 was observed with K(+), Ca(2+), Co(2+), and Na(+); whereas, the enzyme activity was inhibited by Sr(2+), Mn(2+), Fe(2+), Cu(2+),Cd(2+), Mg(2+), and EDTA. Cga-L50 is an endo-type λ-carrageenase that hydrolyzes β-1,4-linkages of λ-carrageenan, yielding neo-λ-carrabiose as the main product. This study is the first to present evidence of thermostable λ-carrageenase from hot spring bacteria.