Optimization of acrylonitrile biodegradation by acrylonitrile-degrading bacterium Rhodococus rhodochrous BX2

Abstract:

[Objective] to improve acrylonitrile biodegradation efficiency, we studied acrylonitrile degradation characteristics of a nitrile-degrading bacterium Rhodococus rhodochrous BX2 isolated by our laboratory. [Methods] Single factor test and response surface methodology were used to optimize the biodegradation conditions. At the same time, the effects of various additional carbon and nitrogen resources on cell growth and acrylonitrile degradation were studied, as well as cell growth and degradation rate of strain BX2 in acrylonitrile synthetic wastewater. [Results] The maximum biodegradation rate (95.1%) was obtained under optimal degradation conditions (substrate concentration 403.51 mg/L, pH 7.44, temperature 34.46 °C). The cell growth and degradation effectiveness can be obviously improved by addition of carbon sources (glucose) or nitrogen source (ammonium chloride). The degradation rate of acrylonitrile in acrylonitrile synthetic wastewater reached 89.4% after 30 h. [Conclusion] the acrylonitrile biodegradation efficiency of Rhodococus rhodochrous BX2 in acrylonitrile synthetic wastewater was enhanced by optimizing biodegradation conditions and the addition of exogenous substance. This work provides technical support for the development and application of new techniques in biological treatment of acrylonitrile wastewater.

Key words:Acrylonitrile, Rhodococus rhodochrous BX2, Response surface methodology, Degradation conditions