Dehalogenation of a mixture of chloroaromatics by immobilized Pseudomonas sp. US1 ex cells

Abstract

Pseudomonas sp. US1 ex e n t r a p p e d in calcium alginate c o u l d d e h a l o g e n a t e a mixture o f i s o m e r i c m o n o c h l o r o b e n z o a t e s a n d 2 , 4 -d i c h l o r o p h e n o x y a e e t i c acid. Rates o f d e h a l o g e n a t i o n by the i m m o b i l i z e d cells were f o u n d to be c o m p a r a b l e to those o f free cells. C o n d i t i o n s for o p t i m u m d e h a l o g e n a t i o n o f c h l o r o a r omatics by i m m o b i l i z e d cells and their reusability were investigated. P r e l i m i n a r y attempts were m a d e to set up a c o n t i n u o u s system for d e h a l o g e n a t i o n o f c h l o r o a r omatics using a fluidized b e d c o l u m n reactor.

Simultaneous degradation of phenol and 3-chlorobenzoate by a mixture of separately immobilized cells of two strainsof Pseudomonas – A preliminary study

“…Similarly, a mixed culture of strains 3mT and P. stutzeri SPC-2, another phenol-degrader with an ortho-pathway also was shown to degrade both these substrates simultaneously (Jayachandran and Kunhi, 2009). However, there seems to be no report on degradation of these two compounds simultaneously by immobilized cells of any organisms, although there have been several reports of degradation of phenol (Agarry et al, 2008;Ahamad and Kunhi, 2011) and a few reports on catabolism of 3-CBA (Sahasrabudhe et al, 1991;Yun et al, 2009) separately by immobilized microbes. In the present study, the complete disappearance of 2 mM each of phenol and 3-CBA occurred within 6 and 7 h, respectively with the release of stoichiometric amounts of Cl¯ whereas with free cells the disappearance of the same amounts of substrates took more than 9 h and the complete mineralization with the release of stoichiometric amount of Cl¯ took about 24 h (Babu et al, 1995a).…”

“…There ISSN (print): 1823-8262, ISSN (online): 2231 are only a few reports on degradation of chlorobenzoates by immobilized systems. Sahasrabudhe et al (1991) have reported dehalogenation of mixtures of monochlorobenzoates and 2, 4-dichlorophenoxyacetic acid by Ca-alginate entrapped cells of Pseudomonas sp. US1 ex, the rates of dehalogenation being comparable to that of free cells.…”

“…CP4 in both Ca-alginate and agar gel beads (Ahamad and Kunhi, 2011). However, there have been hardly few reports on degradation of chlorobenzoates using immobilized cell systems (Sahasrabudhe et al, 1991;Yun et al, 2009) and there seems to be no report at all on simultaneous degradation of phenol and chlorobenzoates by immobilized microbial systems. In the present communication we present some preliminary data on simultaneous degradation of equimolar mixtures of phenol and 3-CBA, in a fluidized bed reactor, by a 1:1 mixture of immobilized cells of strains CP4 and 3mT that were entrapped separately in Ca-alginate gel beads.…”

Fed batch bioconversion of 2-propanol by a solvent tolerant strain of Alcaligenes faecalis entrapped in Ca-alginate gel

“…These immobilized cells are also favourable for investigation of cell physiology and the dissolution of such gel particles (and thus the liberation of the immobilized cells) is easy and rapid. This technique has gained great scientiWc interest and has been used extensively by researchers in degradation studies of compounds such as phenols [35], pentachlorophenols [36], polychlorinated biphenyl [9], 3-chloroanilines [19], and a mixture of monochlorobenzoates and 2, 4-dichlorophenoxyacetic acid [37].…”

Bacterial dehalogenases: biochemistry, genetics, and biotechnological applications.

“…For instance, calcium alginate-entrapped cells of the constructed strain Pseudomonas sp. strain USlex (410) in a fluidized-bed column reactor were used for the continuous dehalogenation of a mixture of the herbicide 2,4-D and all three isomeric monochlorobenzoates (411).…”