Degradation of N-methylpyrrolidone in High Salinity Wastewater by a Halotolerant Microorganism

Abstract

N-methylpyrrolidone (NMP), a nitrogen-containing heterocyclic compound, is widely used in lithium batteries and the refining of lubricants. However, it is also very harmful to human health and the environment. Although NMP is biodegradable, industrial high salinity wastewater can stop microorganisms from growing. To effectively degrade NMP in high salinity wastewater, a halotolerant strain CCZU-X was isolated from sea shrimps. The strain was identified as Staphylococcus lentus through morphology observation and 16S rDNA sequencing. The effects of processing conditions such as salt concentration, pH, and temperature on degradation of high salinity NMP-containing wastewater were investigated using single-factor experiments. Quantitative analysis of degradation efficiency of NMP was conducted by high-performance liquid chromatography. The optimal conditions for CCZU-X to degrade NMP in high salinity wastewater were determined to be at pH 7.0 and 35 °C, and the maximum salt tolerance was 25%. Under optimal conditions (pH 7.0, 35 °C, 1% salt, 2000 mg/L NMP), the NMP degradation efficiency of CCZU-X reached 93%. This strain can effectively degrade NMP in high salinity NMP-containing wastewater, thus can be potentially used in industrial applications.