ABSTRACT
ABSTRACT Mycobacterium sp. YC-RL4 is capable of utilizing a broad range of phthalic acid esters (PAEs) as sole source of carbon and energy for growth. The preliminary studies demonstrated its high degrading efficiency and good performance during the bioprocess with environmental samples. Here, we present the complete genome of Mycobacterium sp. YC-RL4, which consists of one circular chromosome (5,801,417 bp) and one plasmid (252,568 bp). The genomic analysis and gene annotation were performed and many potential genes responsible for the biodegradation of PAEs were identified from the genome. These results may advance the investigation of bioremediation of PAEs-contaminated environments by strain YC-RL4.
Subject(s)
Phthalic Acids/metabolism , Plasticizers/metabolism , Genome, Bacterial , Esters/metabolism , Mycobacterium/metabolism , Plasmids/genetics , Plasmids/metabolism , Soil Microbiology , Soil Pollutants/metabolism , Biodegradation, Environmental , Mycobacterium/isolation & purification , Mycobacterium/classification , Mycobacterium/geneticsABSTRACT
Background Integrated statistical experimental designs were applied to optimize the medium constituents for the production of a dimethyl phthalate (DMP)-degrading strain Bacillus sp. QD14 in shake-flask cultures. A Plackett-Burman design (PBD) was applied to screen for significant factors, followed by the Steepest Ascent Method (SAM) to find the nearest region of maximum response. A Box-Behnken design (BBD) of the Response Surface Methodology (RSM) was conducted to optimize the final levels of the medium components. Results After the regression equation and response surface contour plots were analyzed, the concentrations of glucose, corn meal and NaCl were found to significantly influence the biomass of DMP-degrading bacteria. A combination of 22.88 g/L of glucose, 11.74 g/L of corn meal, and 10.34 g/L of NaCl was optimum for maximum biomass production of Bacillus sp. QD14. A 57.11% enhancement of the biomass production was gained after optimization in shake-flask cultivation. The biomass production of Bacillus sp. QD14 reached 9.13 ± 0.29 × 10(8) CFU/mL, which was an excellent match for the predicted value, and the mean value of the match degree was as high as 99.30%. Conclusion In this work, the key factors affected by the fermentation of DMP-degrading strain Bacillus sp. QD14 were optimized by PBD, SAM and BBD (RSM); the yield was increased by 57,11% in the conditions in our study. We propose that the conditions optimized in the study can be applied to the fermentation for commercialization production.
Subject(s)
Phthalic Acids/metabolism , Bacillus/metabolism , Biodegradation, Environmental , FermentationABSTRACT
Comamonas acidovorans D-4, capable of utilizing dimethylterephthalate (DMT) as the sole carbon source, was isolated from the activated sludge of petrochemical wastewater treatment plant. Almost complete utilization of as high as 0.5% (w/v) DMT was observed in 72 hr. Growth kinetics followed a parallel relation between the growth, DMT utilization and cell associated esterase activity. A cell free broth of DMT grown cells showed an extracellular esterase activity. During the DMT degradation an extracellular accumulation of terephthalic acid was found. Although, C. acidovorans grew on a number of phthalate esters and phthalic acids as the sole carbon source, growth was significantly high on phthalic acids. The potential of this organism in petrochemical pollution abatement is discussed.