Tailoring the Oxidative Stress Tolerance of Clostridium tyrobutyricum CCTCC W428 by Introducing Trehalose Biosynthetic Capability.

Fermentations employing anaerobes always suffer from the restriction of stringent anaerobic conditions during the production of bulk and fine chemicals. This work aims to improve the oxidative stress tolerance of C. tyrobutyricum CCTCC W428, an ideal butyric-acid-producing anaerobe, via the introduction of trehalose biosynthesis capability. Compared with the wild type, the engineered strain showed a wider substrate spectrum, an improved metabolic profile, and a significantly increased specific growth rate upon aeration and acid challenge. Molecular simulation experiments indicated that CoA transferase maintained its native folded state when protected by the trehalose system. Furthermore, qRT-PCR was combined assays for acid-related enzyme activities under various conditions to verify the effects of trehalose. These results demonstrate that introducing a trehalose biosynthetic pathway, which is redundant for the metabolism of C. tyrobutyricum, can increase the robustness of the host to achieve a better oxidative resistance.