TY - JOUR
T1 - Effect of herbicide adjuvants on the biodegradation rate of the methylthiotriazine herbicide prometryn
AU - Pérez-Bárcena, José Fernando
AU - Ahuatzi-Chacón, Deifilia
AU - Castillo-Martínez, Karla Lizzette
AU - Ruiz-Ordaz, Nora
AU - Galíndez-Mayer, Juvencio
AU - Juárez-Ramírez, Cleotilde
AU - Ramos-Monroy, Oswaldo
N1 - Funding Information:
Acknowledgments This work was supported by a grant obtained from SIP, IPN. The authors wish to thank COFAA-IPN and SNI-Conacyt for fellowships to D. Ahuatzi-Chacón, N. Ruiz-Ordaz, C. Juárez-Ramírez and J. Galíndez-Mayer; and to SIP-IPN for the financial support of J. F. Pérez-Bárcena and K. L. Castillo-Martínez.
PY - 2014/6
Y1 - 2014/6
N2 - A microbial community, selected by its ability to degrade triazinic herbicides was acclimatized by successive transfers in batch cultures. Initially, its ability to degrade prometryn, was evaluated using free cells or cells attached to fragments of a porous support. As carbon, nitrogen and sulfur sources, prometryn, (98.8 % purity), or Gesagard, a herbicide formulation containing 44.5 % prometryn and 65.5 % of adjuvants, were used. In batch cultures, a considerable delay in the degradation of prometryn, presumptively caused by the elevated concentration of inhibitory adjuvants, occurred. When pure prometryn was used, volumetric removal rates remarkably higher than those obtained with the herbicide formulation were estimated by fitting the raw experimental data to sigmoidal decay models, and differentiating them. When the microbial consortium was immobilized in a continuously operated biofilm reactor, the negative effect of adjuvants on the rate and removal efficiency of prometryn could not be detected. Using the herbicide formulation, the consortium showed volumetric removal rates greater than 20 g m-3 h-1, with prometryn removal efficiencies of 100 %. The predominant bacterial strains isolated from the microbial consortium were Microbacterium sp., Enterobacter sp., Acinetobacter sp., and Flavobacterium sp. Finally, by comparison of the prometryn removal rates with others reported in the literature, it can be concluded that the use of microbial consortia immobilized in a biofilm reactor operated in continuous regime offer better results than batch cultures of pure microbial strains.
AB - A microbial community, selected by its ability to degrade triazinic herbicides was acclimatized by successive transfers in batch cultures. Initially, its ability to degrade prometryn, was evaluated using free cells or cells attached to fragments of a porous support. As carbon, nitrogen and sulfur sources, prometryn, (98.8 % purity), or Gesagard, a herbicide formulation containing 44.5 % prometryn and 65.5 % of adjuvants, were used. In batch cultures, a considerable delay in the degradation of prometryn, presumptively caused by the elevated concentration of inhibitory adjuvants, occurred. When pure prometryn was used, volumetric removal rates remarkably higher than those obtained with the herbicide formulation were estimated by fitting the raw experimental data to sigmoidal decay models, and differentiating them. When the microbial consortium was immobilized in a continuously operated biofilm reactor, the negative effect of adjuvants on the rate and removal efficiency of prometryn could not be detected. Using the herbicide formulation, the consortium showed volumetric removal rates greater than 20 g m-3 h-1, with prometryn removal efficiencies of 100 %. The predominant bacterial strains isolated from the microbial consortium were Microbacterium sp., Enterobacter sp., Acinetobacter sp., and Flavobacterium sp. Finally, by comparison of the prometryn removal rates with others reported in the literature, it can be concluded that the use of microbial consortia immobilized in a biofilm reactor operated in continuous regime offer better results than batch cultures of pure microbial strains.
KW - Biofilm reactor
KW - Herbicide adjuvants
KW - Methylthiotriazine herbicides
KW - Microbial consortium
KW - Prometryn biodegradation
UR - http://www.scopus.com/inward/record.url?scp=84899427866&partnerID=8YFLogxK
U2 - 10.1007/s10532-013-9669-7
DO - 10.1007/s10532-013-9669-7
M3 - Artículo
C2 - 24166157
SN - 0923-9820
VL - 25
SP - 405
EP - 415
JO - Biodegradation
JF - Biodegradation
IS - 3
ER -