Dimethyl sulfoxide (DMSO) as the sulfur source for the production of desulfurizing resting cells of Gordonia alkanivorans RIPI90A

The sulfate repression of desulfurization (Dsz) phenotype represents a major barrier to the mass production of desulfurizing resting cells. This repression can be avoided by replacing sulfate with dibenzothiophene (DBT) as the main substrate for the 4S pathway. However, mass production of biocatalyst using DBT is impractical because of its high price, low water solubility, and growth inhibition by 2-hydroxybiphenyl (2-HBP), which is the end product of the 4S pathway. In this work, the results showed that readily bioavailable sulfur compounds led to repression of the desulfurization activity of Gordonia alkanivorans RIPI90A. However, the Dsz phenotype was expressed through the 4S pathway in the presence of DMSO as the sulfur source for growth. Resting cells grown on DMSO were more active than the resting cells grown on DBT. The growth rate of strain RIPI90A on DMSO was higher than when DBT was used as the sole sulfur source. DMSO concentration significantly influenced the growth pattern of the strain, and the highest, growth rate was observed at a concentration of 200 ?g ml-1. Above this concentration, the growth rate gradually decreased. DBT was found to induce the Dsz phenotype, with no observed lag period, in cells grown on DMSO as the sole sulfur source