Detection of <i>meta</i> - and <i>ortho</i> -cleavage dioxygenases in bacterial phenol-degraders

Abstract

ABSTRACT:In the last five years, in our lab, several bacterial genera capable of degrading phenol as sole carbon source were isolated from different Egyptian ecosystems. Phenol mineralization using these isolates was ranged from 55% to 0.4%. In the present work, randomly chosen representative strains; W-17, DF4 (Acinetobacter), Sea-8 (Stenotrophomonas), W-6 (Klebsiella), S-5 (Bacillus) and W-15 (Ralstonia) were analyzed for the type of ring-cleavage (ortho or meta) dioxygenase physiologically induced during growth in the presence of phenol as a sole carbon and energy source. The specific activities of the phenol-degrading enzymes phenol hydroxylase, catechol-1,2-dioxygenase and catechol-2,3-dioxygenase were investigated. In addition, whole-cell dioxygenases activities of the examined isolates were determined. Out of the results, only the Acinetobacter strains W-17 and DF-4 showed activity with the enzymes phenol hydroxylase and catechol-1,2-dioxygenase, which responsible for phenol degradation through ortho-cleavage pathway. In contrast, isolates S-5, Sea-8, W-6, W-15 and Pla-1 showed activity with the enzyme catalyzing the second step in the phenol degradation meta-cleavage pathway, catechol-2,3-dioxygenase. On the basis of our previous and present analysis, the investigated isolates are considered to have a good potential for application in remediation of phenol contaminated environments and industrial wastewater. @JASEM Phenol and phenolic compounds are of widespread use in many industries such as polymeric resin production and oil refining. As a result, these compounds are commonly encountered in industrial effluents and surface water. These pollutants are usually treated in activated sludge processes because many aerobic bacteria and fungi are able to use phenol as a source of carbon and energy (Rebhun and Galil 1988;Watanabe et al., 1996). Biodegradation of phenol, therefore, has long been the subject of numerous investigations (Ruiz-Rrdaz et al

Isolation and characterization of a novel strain of Stenotrophomonas maltophilia possessing various dioxygenases for monocyclic hydrocarbon degradation

“…Lack of monooxygenase activity after benzoate induction (data not shown) also confirmed that hypothesis. Among the Stenotrophomonas maltophilia species only one described as strain Sea-8 was found to express catechol dioxygenases activities after phenol induction, although the activity of catechol 2,3-dioxygenase in that case was rather small (28). Contrary to Sea-8 strain, Stenotrophomonas maltophilia strain KB2 growing on 3 mM phenol showed trace activity of intradiol catechol dioxygenase (Table 3).…”

“…A high percentage identity was also found with Stenotrophomonas sp. strain Sea-8, a phenol degrader (28) (Fig. 1).…”

“…Although Stenotrophomonas species capable of degrading aromatic compounds have been reported earlier (4,17) little has been investigated on the possibility of occurrence of the heterogeneous metabolic pathways in one strain of this genus (28). So far Stenotrophomonas species were mainly described as polycyclic hydrocarbon degraders or opportunistic human pathogens (2,3,4,8,10).…”

Isolation, biochemical and molecular characterization of 2-chlorophenol-degrading Bacillus isolates

“…However, these results do not mean that the other three isolates QUCASBSD-2, QUCASBSD-4 and QUCASBSD-5 are not 2-chlorophenol degraders. It is known that the degradation of phenol and its derivatives takes place aerobically through two main metabolic pathways; initiated by ortho-or meta-cleavage (Zaki, 2006). The enzymes phenol hydroxylase and catechol 1,2-dioxygenase or 2,3-dioxygenase catalyze the first and the second steps of phenol degradation, respectively (Gaal and Neujahr, 1979) which need to be covered for the isolated strains in next studies.…”

Molecular Identification of Phenol-Degrading and Biofi lm-Forming Bacteria from Wastewater and Peat Soil

“…However, phenols are more commonly produced as artifi cal aromatic compounds in wastewater from many industries, such as textile, dye, oil refi nery, chemical instalation, and medical (Lee et al, 1997;Tsai et al, 2005;Al-Thani et al, 2007;Anonim, 2008). Phenol is relatively soluble in water, and the wastewater containing this compound can contaminate and accumulate in soil, surface water, and ground water (Zaki, 2006;Mahiuddin et al, 2012). This corrosive compound can be absorbed through inhalation, digestion, also skin, and may cause chemical burn, promotes tumor (Bitton, 2005;Anonim, 2008;Chakraborty et al, 2010), also affect the function of human and animal hormonal system (Aoyama et al, 2012).…”