Isolation of a novel thermostable dehydrochlorinase (LinA) from a soil metagenome.

Hexachlorocyclohexane dehydrochlorinase (LinA) mediates first step of aerobic degradation of a chlorinated insecticide γ-hexachlorocyclohexane (γ-HCH). In this study, we describe characterization of a novel variant (LinA-type2) that is distinct from reported LinAs and is substantially more thermostable than archetypal LinA-UT26. LinA-type2 remains active even after 8 h of incubation at 45 °C, when nearly 50% activity of LinA-UT26 is lost after incubation for 60 min at the same temperature. Circular dichroism analysis revealed that secondary structures of LinA-UT26 and LinA-type2 are similar, but their Tm was 45 and 65 °C, respectively. Thermostability of LinA-type2 makes it suitable for bioreactors where allowance for higher temperatures can be of advantage.