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Evaluation of different phenol hydroxylase-possessing phenol-degrading pseudomonads by kinetic parameters.
Biodegradation ( IF 3.6 ) Pub Date : 2008-02-20 , DOI: 10.1007/s10532-008-9180-8
Signe Viggor 1 , Eeva Heinaru , Allan Künnapas , Ain Heinaru
Affiliation  

Phenol-degrading pseudomonads possessing different phenol hydroxylases (PH) were evaluated by the values of apparent half-saturation constant for phenol-oxygenating activity (K ( S )), maximum specific growth rate (mu (max)), lag-time length (lambda), inhibition constant (K ( I )) and growth yield factor (Y ( X/S )). Strains of the same PH type showed similar kinetic parameters: single-component PH (sPH) harbouring strains had higher values of K ( S ) and lower values of mu (max) than the strains having multicomponent PH (mPH). However, the values of K ( I ) and the dependencies of the lag-time length on initial phenol concentration were strain-specific. The elevated ratio between specific activities of catechol 1,2-dioxygenase (C12O) and muconate cycloisomerase in sPH-strains caused irreversible accumulation of a high amount of exogenous cis,cis-muconate (CCM) which resulted in decreased Y ( X/S ) values. Co-presence of sPH and mPH genes did not give the strains PC16 and P69 any extra advantage and according to determined kinetic parameters only one PH was active during phenol degradation. At the same time simultaneous functioning of catechol ortho and meta cleavage pathways (strain PC20) resulted in higher mu (max) and Y ( X/S ) values. Evaluation of strains showed that the type of PH determined the efficiency of phenol degradation, whereas the tolerance to elevated phenol concentrations was strain-specific.

中文翻译:

通过动力学参数评估不同的具有苯酚羟化酶的可降解苯酚假单胞菌。

通过苯酚氧化活性的表观半饱和常数(K(S)),最大比生长速率(mu(max)),滞后时间长度()来评估具有不同苯酚羟化酶(PH)的降解苯酚的假单胞菌。 λ),抑制常数(K(I))和生长产量因子(Y(X / S))。具有相同PH类型的菌株显示出相似的动力学参数:与具有多组分PH(mPH)的菌株相比,具有单组分PH(sPH)的菌株具有更高的K(S)值和更低的mu(max)值。但是,K(I)值和滞后时间长度对初始酚浓度的依赖性是特定于菌株的。sPH菌株中邻苯二酚1,2-二加氧酶(C12O)和粘液酸环异构酶的比活比升高,导致大量外源顺式不可逆积累,顺式粘液酸盐(CCM),导致Y(X / S)值降低。sPH和mPH基因的共存并没有给PC16和P69菌株带来任何额外的优势,根据确定的动力学参数,苯酚降解过程中只有一个PH是有活性的。同时,邻苯二酚邻位和间位裂解途径(PC20菌株)的同时运行导致更高的mu(max)和Y(X / S)值。菌株评估表明,PH的类型决定了苯酚降解的效率,而对升高的苯酚浓度的耐受性则是菌株特异性的。同时,邻苯二酚邻位和间位裂解途径(PC20菌株)的同时运行导致更高的mu(max)和Y(X / S)值。菌株评估表明,PH的类型决定了苯酚降解的效率,而对升高的苯酚浓度的耐受性则是菌株特异性的。同时,邻苯二酚邻位和间位裂解途径(PC20菌株)的同时运行导致更高的mu(max)和Y(X / S)值。菌株评估表明,PH的类型决定了苯酚降解的效率,而对升高的苯酚浓度的耐受性则是菌株特异性的。
更新日期:2019-11-01
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