Artificial microbial consortium for simultaneous removal of dibutyl phthalate and atrazine combined pollutants at low temperatures

Abstract

Combined organic pollutants pose common and serious threats to the global eco-environment. Dibutyl phthalate (DBP) and atrazine (ATZ) are major toxic organic pollutants. However, there are no microorganisms capable of simultaneously removing these two organic pollutants from aquatic systems. An artificial microbial consortium has been considered a promising approach to achieve high removal efficiencies of DBP and ATZ. Therefore, the DBP and ATZ degrading strains, namely Rhodococcus KD0901 and Paenarthrobacter sp. KN0901, were co-cultured in this study based on the metabolic division of labor (MDOL) to construct a KDN0901 consortium. The constructed KDN0901 consortium simultaneously degraded 100 mg·L-1 and 30 mg·L-1 of DBP and ATZ, respectively, within three days of incubation at 15 °C. In addition, KDN0901 showed high adaptability to different pH and temperature conditions, from 5 to 9 and from 4 °C to 35 °C, respectively, especially at low temperatures. According to the constructed cross-feeding model using metabolic analyses, KD0901 provided KN0901 with n-butanol, while KN0901 provided KD0901 with ethylamine and isopropylamine. In this study, DBP and ATZ resulted in serious toxicity in soybean (G. max) plants, negatively affecting the growth, photosynthesis, and oxidative stress of the plants. However, the length and biomass of the plants increased by 33.3 % and 273.7 %, respectively, following the KDN0901 treatment, demonstrating the effectiveness of KDN0901 in mitigating the combined toxicity of DBP and ATZ. This study provided an effective, economical, and eco-friendly approach to promoting highly efficient and simultaneous bioremediation of DBP and ATZ-related pollution, especially in cold areas.