Isolation of a CX-DBT desulfurizing strain and optimization of its fermentation conditions

Abstract:

[Objective] The objective of this study is to isolate and identify a novel bacterial strain capable of selectively desulfurizing CX-DBT, and then to determine its desulfurizing pathway and optimize the culture condition. [Methods] CX-DBT was used as the sole sulfur resource to enrich the bacterial cultures, and then GC-MS was used to determine CX-DBT desulfurizing pathway by analyzing the metabolic productions. The new culture, strain JDZX13, was identified based on the morphological, physiological and biochemical properties, and 16S rRNA gene sequence profiles. Single factor test and orthogonal design method were performed to determine the optimal biodesulfurizaio conditions. [Results] The new strain JDZX13 belonged to Gordonia sp. and named as Gordonia sp. JDZX13 (KP993297), which could selectively desulfurize CX-DBT by “4S pathway”. The optimum operating conditions were found as 15 g/L of sucrose, 2 g/L of NH4Cl, 0.1 g/L of MgCl2, 1 mL of metal solution, at pH 7.0 and 35 °C. [Conclusion] A bacterial strain JDZX13 was successfully isolated and identified with the utilization of CX-DBT by “4S pathway”. After a serial optimizations, the cell growth and desulfurizing capability were further enhanced. This result would be an important reference for further exploring the petroleum biodesulfurization technology.