Cometabolic degradation of 4-chlorophenol by Alcaligenes eutrophus

Abstract

Alcaligenes eutrophus was grown in batch cultures using either phenol as a sole substrate or mixtures of phenol and 4-chlorophenol. Phenol was found to be the sole source for carbon and energy while 4-chlorophenol was utilized only as a cometabolite. Maximum growth rates on phenol reached only 0.26 h-1, significantly below the growth rates reported earlier with Pseudomonas putida. The cometabolite was found to decrease biomass yield and increase lag time before logarithmic growth occurred. Both phenol and 4-chlorophenol were found to inhibit the growth rate linearly with maximum concentrations of 1080 ppm and 69 ppm respectively, beyond which no growth occurred. The best-fit parameters are incorporated into a simple, dynamic (i.e. time-varying) model capable of predicting all the batch growth conditions presented here. It is shown that P. putida is capable of faster bioremediation when phenol is the sole carbon source or for mixed substrates with low concentrations of the cometabolite, but for high concentrations of 4-chlorophenol, A. eutrophus becomes superior because of the long lag times that occur in the Pseudomonas species.

Modeling chlorophenols degradation in sequencing batch reactors with instantaneous feed-effect of 2,4-DCP presence on 4-CP degradation kinetics

“…Although, the degradation of CHMS was achieved after acclimation of cultures, it has been widely reported as being a dead-end metabolite, especially for pure cultures (Sae'z and Rittmann 1993; Hill et al 1996). Therefore, mixed cultures are particularly important when the emphasis is placed on complete mineralization of toxic organics to CO 2 .…”

Kinetic study of phenol hydroxylase and catechol 1,2-dioxygenase biosynthesis by Candida tropicalis cells grown on different phenolic substrates

“…Numerous bacteria are known to degrade phenolic compounds, mainly from the genera Alcaligenes (Hill et al 1996), Arthrobacter (Westerberg et al 2000), Pseudomonas (Kiyohara et al 1992;Armenante & Kafkewitz 1995), Comamonas (Hollender et al 1994), Rhodococcus (Briglia et al 1996;Moiseeva et al 1999), and Ralstonia (Steinle et al 1998). …”

Arthrobacter chlorophenolicus sp. nov., a new species capable of degrading high concentrations of 4-chlorophenol.

“…Several other problems may also arise in a bioaugmentation scenario. For example, 4-CP degradation might be restricted to co-metabolism in the presence of an inducer, such as phenol (Hill et al, 1996), or dead-end meta-K. Westerberg and others bolites may accumulate (Ihn et al, 1989 ;Wieser et al, 1994). Thus, when selecting a micro-organism for bioaugmentation, one needs to consider these potential problems.…”