TY - JOUR
T1 - Transformation of dimethyl phthalate, dimethyl isophthalate and dimethyl terephthalate by Rhodococcus rubber Sa and modeling the processes using the modified Gompertz model
AU - Li, Jiaxi
AU - Gu, Ji Dong
AU - Pan, Li
N1 - Funding Information:
This project was supported by the Chinese Academy of Sciences. Additional financial support was by a SCSIO Knowledge Innovation project LYQY200306 and an 863 project No. 2002AA601160.
PY - 2005/4
Y1 - 2005/4
N2 - Phthalate ester isomers, including dimethyl phthalate (DMP), dimethyl isophthalate (DMI) and dimethyl terephthalate (DMT), were found to be transformed by Rhodococcus rubber Sa isolated from a mangrove sediment using DMT as a carbon source initially. At a concentration of 80 mg l-1, transformation of DMP, DMI and DMT was achieved in 9, 1 and 5 days, respectively. During the hydrolytical transformation of DMP, DMI and DMT, their corresponding intermediates were identified as mono-methyl phthalate (MMP), mono-methyl isophthalate (MMI) and mono-methyl terephthalate (MMT), suggesting that transformation of all three isomers followed an identical biochemical pathway of de-esterification. However, none of the produced monoesters was further transformed by R. rubber Sa and they accumulated in the culture media during incubation. It seems that further transformation of monoesters require a set of hydrolytic enzymes different from those involved in the first transformation reaction. Kinetics of DMT, DMI and DMP transformation was well described by the modified Gompertz model independent of the individual substrate condition or a mixture of the three isomers. Both DMI and DMT were easier transformed substrates than DMP, resulting in higher maximum transformation rate (Rm) and shorter lag time phase (λ) derived from the modified Gompertz model. The modified Gompertz model based on one-substrate system can be used in fitting transformation kinetics of mixture substrate system. Our data suggest that degradation of phthalate diesters involves different enzymes in the hydrolysis of the two identical ester groups.
AB - Phthalate ester isomers, including dimethyl phthalate (DMP), dimethyl isophthalate (DMI) and dimethyl terephthalate (DMT), were found to be transformed by Rhodococcus rubber Sa isolated from a mangrove sediment using DMT as a carbon source initially. At a concentration of 80 mg l-1, transformation of DMP, DMI and DMT was achieved in 9, 1 and 5 days, respectively. During the hydrolytical transformation of DMP, DMI and DMT, their corresponding intermediates were identified as mono-methyl phthalate (MMP), mono-methyl isophthalate (MMI) and mono-methyl terephthalate (MMT), suggesting that transformation of all three isomers followed an identical biochemical pathway of de-esterification. However, none of the produced monoesters was further transformed by R. rubber Sa and they accumulated in the culture media during incubation. It seems that further transformation of monoesters require a set of hydrolytic enzymes different from those involved in the first transformation reaction. Kinetics of DMT, DMI and DMP transformation was well described by the modified Gompertz model independent of the individual substrate condition or a mixture of the three isomers. Both DMI and DMT were easier transformed substrates than DMP, resulting in higher maximum transformation rate (Rm) and shorter lag time phase (λ) derived from the modified Gompertz model. The modified Gompertz model based on one-substrate system can be used in fitting transformation kinetics of mixture substrate system. Our data suggest that degradation of phthalate diesters involves different enzymes in the hydrolysis of the two identical ester groups.
KW - Biotransformation
KW - Dimethyl isophthalate
KW - Dimethyl phthalate
KW - Dimethyl terephthalate
KW - Gompertz model
KW - Mixed substrates
UR - http://www.scopus.com/inward/record.url?scp=15944368633&partnerID=8YFLogxK
U2 - 10.1016/j.ibiod.2004.12.003
DO - 10.1016/j.ibiod.2004.12.003
M3 - 文章
AN - SCOPUS:15944368633
SN - 0964-8305
VL - 55
SP - 223
EP - 232
JO - International Biodeterioration and Biodegradation
JF - International Biodeterioration and Biodegradation
IS - 3
ER -