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Characterization and overexpression of a novel β-agarase from Thalassomonas agarivorans

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Abstract

Aims

The agarase from Thalassomonas agarivorans BCRC 17492 was cloned and overexpressed in Escherichia coli. The characterization of the novel agarase was performed.

Methods and Results

The genomic library of T. agarivorans BCRC 17492 was constructed for screening agarase gene. The novel β-agarase, namely AgaB1, was successfully identified and shared only 57% identity to reported agarase from Alteromonas sp. To characterize the AgaB1 protein, the recombinant AgaB1 can be obtained by heterologous expression in E. coli. The agarase activity of AgaB1 was achieved at 30·25 U per mg at 35°C. According to the analysis of optimal conditions, the highest activity of AgaB1 was attained at 40°C, pH 7·4 and 200 mmol l−1 NaCl, and half-life of AgaB1 can be maintained for almost 1 h at 40°C. Further determination of substrate hydrolysis indicated that AgaB1 had possession of both endo- and exolytic activity, and neoagarobiose was the major hydrolysis product by TLC and high-performance liquid chromatograph/mass spectrometer (HPLC/MS) analysis.

Conclusions

We have successfully cloned and overexpressed the novel β-agarase from T. agarivorans BCRC 17492 in E. coli. The high yield and detailed characterization of recombinant AgaB1 was provided.

Significant and Impact of the study

AgaB1 was the first β-agarase that was cloned and described from Thalassomonas species. In the light of properties of AgaB1, it has the potential as the biocatalyst for industrial applications.

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