39
intermediate and the hydroxy analogues. The methylthio group of methylthio- striazines was progressively oxidised and hydrolysed (Fujii et al. 2007). Simazine
degradation occurs via two pathways yielding either 2-hydroxysimazine or desethylsimazine. Organic or inorganic nitrogen sources stimulated N5C cell growth, but
had little effect on the simazine degradation rate. Some of the bacteria use prometryn or ametryn as the sole source of sulphur for growth (Cook and Hütter 1982).
Methylthio-s-triazines were transformed to their hydroxy compounds by whole
cells and cell extracts of Nocardioides sp. strain C190 (Topp et al. 2000) and
Clavibacter michiganensis strain ATZ1 (Seffernick et al. 2000). Recombinant TrzN
from Arthrobacter aurescens strain TC1 rapidly hydrolyses ametryn and methylsufinyl ametryn to hydroxyametryn (Shapir et al. 2005a).
S-Triazine-Degrading Proteins
AtzA is a homohexamer of the amidohydrolase superfamily which contains one
essential Fe
2+
per monomer. AtzA hexamer is a trimer of dimers with a molecular
weight of 315 kDa. AtzA gene has been proposed to be evolved from the TriA gene
Fig. 2.3 Cyanuric acid
degradative pathway
showing conversion of
cyanuric acid to carbon
dioxide and ammonia
2 Biodegradation and Bioremediation of S-Triazine Herbicides
intermediate and the hydroxy analogues. The methylthio group of methylthio- striazines was progressively oxidised and hydrolysed (Fujii et al. 2007). Simazine
degradation occurs via two pathways yielding either 2-hydroxysimazine or desethylsimazine. Organic or inorganic nitrogen sources stimulated N5C cell growth, but
had little effect on the simazine degradation rate. Some of the bacteria use prometryn or ametryn as the sole source of sulphur for growth (Cook and Hütter 1982).
Methylthio-s-triazines were transformed to their hydroxy compounds by whole
cells and cell extracts of Nocardioides sp. strain C190 (Topp et al. 2000) and
Clavibacter michiganensis strain ATZ1 (Seffernick et al. 2000). Recombinant TrzN
from Arthrobacter aurescens strain TC1 rapidly hydrolyses ametryn and methylsufinyl ametryn to hydroxyametryn (Shapir et al. 2005a).
S-Triazine-Degrading Proteins
AtzA is a homohexamer of the amidohydrolase superfamily which contains one
essential Fe
2+
per monomer. AtzA hexamer is a trimer of dimers with a molecular
weight of 315 kDa. AtzA gene has been proposed to be evolved from the TriA gene
Fig. 2.3 Cyanuric acid
degradative pathway
showing conversion of
cyanuric acid to carbon
dioxide and ammonia
2 Biodegradation and Bioremediation of S-Triazine Herbicides