Rapid Mineralization of the Phenylurea Herbicide Diuron by Variovorax sp. Strain SRS16 in Pure Culture and within a Two-Member Consortium

Abstract

The phenylurea herbicide diuron [N-(3,4-dichlorophenyl)-N,N-dimethylurea] is widely used in a broad range of herbicide formulations, and consequently, it is frequently detected as a major water contaminant in areas where there is extensive use. We constructed a linuron [N-(3,4-dichlorophenyl)-N-methoxy-N-methylurea]-and diuron-mineralizing two-member consortium by combining the cooperative degradation capacities of the diuron-degrading organism Arthrobacter globiformis strain D47 and the linuron-mineralizing organism Variovorax sp. strain SRS16. Neither of the strains mineralized diuron alone in a mineral medium, but combined, the two strains mineralized 31 to 62% of the added [ring-U-14 C]diuron to 14 CO 2 , depending on the initial diuron concentration and the cultivation conditions. The constructed consortium was used to initiate the degradation and mineralization of diuron in soil without natural attenuation potential. This approach led to the unexpected finding that Variovorax sp. strain SRS16 was able to mineralize diuron in a pure culture when it was supplemented with appropriate growth substrates, making this strain the first known bacterium capable of mineralizing diuron and representatives of both the N,N-dimethyl-and N-methoxy-N-methyl-substituted phenylurea herbicides. The ability of the coculture to mineralize microgram-per-liter levels of diuron was compared to the ability of strain SRS16 alone, which revealed the greater extent of mineralization by the two-member consortium (31 to 33% of the added [ring-U-14 C]diuron was mineralized to 14 CO 2 when 15.5 to 38.9 g liter ؊1 diuron was used). These results suggest that the consortium consisting of strains SRS16 and D47 could be a promising candidate for remediation of soil and water contaminated with diuron and linuron and their shared metabolite 3,4-dichloroaniline.

Aerobic Mineralization of Nitroguanidine by Variovorax Strain VC1 Isolated from Soil

“…The strain was named Variovorax strain VC1. Variovorax species display multiple metabolic features including the biotransformation of the herbicides linuron 13 and diuron 14 and of synthetic (2,4-dinitrotoluene) and naturally occurring (3-nitrotyrosine) nitroaromatic compounds. 15,16 Growth of VC1 with NQ as the sole nitrogen source in the presence of 10 mM glucose is presented in Figure 2a.…”

Degradation of paracetamol by pure bacterial cultures and their microbial consortium

“…Joshi et al (2008) reported acid orange decolorization was significantly higher with the use of consortium as compared to the use of individual strains. Bacterial cocultures have been used to increase the rate of degradation of phenol (Jiang et al 2006) and diuron (Sørensen et al 2008 …”

Enhanced Agarose and Xylan Degradation for Production of Polyhydroxyalkanoates by Co-Culture of Marine Bacterium, Saccharophagus degradans and Its Contaminant, Bacillus cereus

“…Dutta et al [48] described that root colonization and promotion of growth can be affected due to root exudates prompting alterations in the cell surface of B. cereus. Dead microbial structures can possibly work as nutrient source for the growth of strains in the co-culture [49].…”