RSM optimization of dibenzothiophene biodesulfurization by newly isolated strain of Rhodococcus erythropolis PD1 in aqueous and biphasic systems

Autor: Peyman Derikvand, D. Biria, Zahra Etemadifar
Rok vydání: 2015
Předmět:
Zdroj: Microbiology. 84:65-72
ISSN: 1608-3237
0026-2617
DOI: 10.1134/s002626171501004x
Popis: Dibenzothiophene (DBT) is a recalcitrant organic sulfur compound which remains in the crude oil after hydrodesulfurization (HDS) process and can be removed by biodesulfurization (BDS). The objective of this study was the isolation of novel strain capable more BDS rate and optimization of DBT removal by both growing and resting cells. Response surface Methodology (RSM) was applied for evaluating the interactive effects of three independent factors including DBT concentration, temperature and pH. The three factors Box-Benken design with three center points was performed to generate the optimum condition for DBT removal by growing cells in aqueous medium and resting cells in biphasic medium. Among the isolated bacteria from oil-contaminated soil, a gram-positive, non-spore forming isolate designated PD1 showed the high BDS rate and capable to convert the DBT to 2-hydroxybiphenyl (2-HBP) as the final product. Analysis of variance (ANOVA) demonstrated that all of the studied parameters in the growing cells system showed significant effect on BDS rate, while in the resting cells effect of pH was not significant (P > 0.05). Maximum 2-HBP production (0.21 mM) by growing cells of PD1 strain was obtained at 0.38 mM initial DBT concentration, pH 6.88 and temperature of 27.57°C. For resting cells, maximum BDS activity of PD1 strain was determined as 0.46 μM 2-HBP/min g DCW at optimum pH 6.29, temperature of 26.13°C and DBT concentration of 7.73 mM. The BDS efficiency of Rhodococcus erythropolis PD1 (NCBI Gene Bank Accession no. JX625154) was increased by setting each factor at the optimum level.
Databáze: OpenAIRE
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