Mutational loss of carotenoids in alkaliphilic Bacillus pseudofirmus OF4 results in sensitivity to oxidative stress and growth at high pH.

ABSTRACT: Alkaliphilic Bacillus pseudofirmus OF4, which has a broad pH growth range of 7.5 to above 10.5, is yellow-pigmented due to carotenoids. Carotenoids contribute to membrane rigidity and can alleviate cellular oxidative stress. This study was undertaken to gain insight into the roles carotenoids play in alkaliphile physiology. Carotenoid content was high in stationary phase and in cells grown nonfermentatively at pH 10.5 A colourless mutant was isolated by the in-frame deletion of a key carotenogenic gene, crtM. In cells grown to stationary phase in a pH 10.5 medium with a suboptimal concentration of Na⁺, the ∆crtM strain exhibited lower resistance to paraquat and hydrogen peroxide. Preincubation of the mutant in a nutrient-free pH 10.5 buffer revealed a pronou

SUBMITTER: Hicks DB 

PROVIDER: S-EPMC7137769 | biostudies-literature | 2019 Sep

REPOSITORIES: biostudies-literature