Isolation of the stable strain Labrys sp. BK-8 for L(+)-tartaric acid production.

A novel cis-epoxysuccinate hydrolase (CESH) producing strain of Labrys sp. BK-8 for production of L(+)-tartaric acid was isolated and identified. After optimization, a maximum activity of 3597 ± 151 U/g was achieved in batch culture in a 10 L fermentor. When Labrys sp. BK-8 was immobilized on κ-carrageenan, the immobilized cells showed a high conversion rate (>99%), enantioselectivity (EE > 99.5%) and storage stability (>90 d). A conversion rate of 97% was still achieved after 10 repeat batches. The CESH was stable over a broad range of temperatures (up to 45°C) and pH values (4.0-10.0). The Labrys sp. BK-8 isolate provides a new alternative with good stability for the industrial biosynthesis of L(+)-tartaric acid.