Temperature-responsive regulation of the polycyclic aromatic hydrocarbon-degrading mesophilic bacterium <i>Novosphingobium pentaromativorans</i> US6-1 with a temperature adaptation system

Survivability and tolerance of polycyclic aromatic hydrocarbon (PAH)-degrading bacteria in harsh environments, especially under varying temperatures, are a bottleneck for the effective application of <i>in situ</i> bioremediation. In this study, a temperature adaptation system (TAS) was constructed by combining a customized thermotolerant system with a customized cold-resistant system to realize the temperature-responsive regulation of the PAH-degrading mesophilic bacterium <i>Novosphingobium pentaromativoran</i>s US6-1. The innovative dual-pronged TAS strategy enabled the chassis strain to effectively tackle conditions under varying temperatures, ensuring robust biological activities across a broadened temperature spectrum and exhibiting the potential to realize the high-efficiency PAH degradation of <i>N. pentaromativorans</i> US6-1 in <i>in situ</i> bioremediation. Furthermore, the temperature-responsive regulation achieved using the TAS circuit is likely promising for creating intelligent microbial cell factories and avoiding precise temperature maintenance, making it highly useful for industrial applications.IMPORTANCEEnvironmental temperature is among the extremely important factors that determine the bioactivities of pollutant-degrading microorganisms in <i>in situ</i> bioremediation. Effectively maintaining the survivability and tolerance of mesophilic microorganisms under harsh conditions and varying temperatures remains a challenge in the application of pollutant bioremediation. This study, for the first time, developed a temperature adaptation system by combining a customized thermotolerant system with a customized cold-resistant system to realize the temperature-responsive regulation of the polycyclic aromatic hydrocarbon (PAH)-degrading mesophilic bacterium <i>Novosphingobium pentaromativoran</i>s US6-1, thus diminishing the need for precise temperature control in PAH bioremediation.