Factors limiting success of inoculation to enhance biodegradation of low concentrations of organic chemicals

Zaidi, Baqar R.; Murakami, Yoshitaka; Alexander, Martin

doi:10.1021/es00177a005

Cited by 25 publications

(15 citation statements)

References 16 publications

(30 reference statements)

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“…In addition, N and P are required in relatively high concentrations; sulphur, iron, calcium and magnesium are required in lower amounts (Atlas et al 1976). Recently the activity of the introduced bacterium into lake water was shown to be limited by the availability of P (Jones and Alexander 1988;Zaidi et al 1988) and the mineralization of para-nitrophenol (PNP) was enhanced by the addition of 100-0 mg I-' of P to lake water. Thus, the phosphate con- centration is central to the metabolic rates of aquatic communities because most major elements of the cell can be derived from the excess N, C, water and sulphate and no such reserves exist for P (Robertson and Button 1979).…”

Section: Introductionmentioning

confidence: 99%

A variable response of degrading bacteria to phosphorus added to natural water

Ramadan

1994

Journal of Applied Bacteriology

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The effect of inorganic phosphorus (P) on the degradation of 10 mg l-1 of para-nitrophenol (PNP) or 2,4-dichlorophenoxyacetic acid (2,4-D) by three test bacteria inoculated into Nile water samples was investigated. The response of the organisms to P depended mainly on their affinity for the available P. Thus, Corynebacterium sp. at an initial density of 3.3 x 10(4) cells ml-1 readily degraded 10 mg l-1 of PNP in filter-sterilized Nile water supplemented with 22.8 mg l-1 of P. The same effect was observed when Pseudomonas cepacia was inoculated into Nile water amended with PNP and supplemented with 2.28-22.8 mg l-1 of P. The bacteria grew in Nile water and the final densities were related to the level of the added P. On the other hand, the addition of P, at concentrations ranging from 2.28 to 22.8 mg l-1, to sterile Nile water inoculated with Pseudomonas sp. and amended with 10 mg l-1 of 2,4-D did not stimulate the degradation compared with that obtained with the unsupplemented samples. The affinity of the three strains to P was demonstrated in P-deficient medium amended with PNP or 2,4-D as a sole carbon source. The pH of the medium was adjusted with 0.1 mol l-1 Tris buffer. Pseudomonas sp. at an initial density of 3.3 x 10(4) cells ml-1 degraded 10 mg l-1 of 2,4-D in non-sterile Nile water without added P. A slight enhancement of degradation was observed in water samples amended with a high concentration of P.(ABSTRACT TRUNCATED AT 250 WORDS)

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Section: Introductionmentioning

confidence: 99%

A variable response of degrading bacteria to phosphorus added to natural water

Ramadan

1994

Journal of Applied Bacteriology

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“…The possible use of bacterial inoculation to effect the biodegradation of low levels of pollutants has been reported [20,21]. However, the introduction into a polluted site of a microbial population with the capability to degrade a toxicant may not always produce the desired outcome [2].…”

Section: Introductionmentioning

confidence: 99%

Selecting inocula for the biodegradation of organic compounds at low concentrations

Pahm

Alexander

1993

Microb Ecol

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The inability of many organisms to degrade pollutants at low concentrations is a problem when selecting inocula for bioremediation of sites with these low concentrations. Thus, a study was conducted to determine the effect of low concentrations of p-nitrophenol (PNP) on growth of four PNP-degrading bacteria and their abilities to metabolize low concentrations of the compound in culture and samples from an oligotrophic lake. PNP did not increase the growth rates of Flavobacterium sp. M4, Pseudomonas sp. K, Flavobacterium sp. M1, and Pseudomonas sp. SP3 at concentrations of less than 2, 4, 10, and 100 ng/ml, respectively, when it was the sole added carbon source in culture, but it stimulated multiplication at higher concentrations. In liquid culture with the nitro compound as sole added carbon source, the four bacteria extensively mineralized PNP at 50 and 100 ng/ml, and three of the four degraded much of the substrate at 25 ng/ml. Pseudomonas sp. SP3 mineralized more than 20% but the two Flavobacterium strains converted less than 10% of the substrate to C02 at 10 ng/ml, and none of the three mineralized more than 5% at 1 and 5 ng PNP/ml. Under conditions where more than 99% of the radioactivity from (14)C-PNP added at 1 ng/ml remained in solution, two of the isolates formed organic products. Pseudomonas sp. K had no activity at 1, 5, and 10 ng/ml. In contrast, when each of the bacteria was separately inoculated into samples of water from an oligotrophic lake and from a well in which PNP was not biodegraded, the bacteria were able to mineralize as little as 1 ng PNP/ml. The addition to a salts solution of 10 ng of glucose per ml resulted in mineralization of PNP at concentrations too low to be mineralized when the nitro compound was the sole source of added carbon. Bacteria may thus be able to mineralize substrates in natural waters at concentrations below those suggested by tests conducted in culture media, possibly because of the availability of other carbon sources for the bacteria.

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“…If an organism capable of degrading a contaminant does not encounter concentrations of the substrate high enough to support growth, degradation may not occur because of the need for the microbes to grow in order to cause degradation (Boethling and Alexander 1979;Zaidi, Murakami, and Alexander 1988). Alternatively, if organisms destroy the compound by cometabolic mechanisms, but lack sufficient cosubstrates to support growth, then the enzymes needed to break down the contaminant will not be produced.…”

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confidence: 99%

“…They may also serve to decrease contaminant levels to levels which are too low. In this event, biological removal may become poor because of scarcity of substrate (Zaidi, Murakami, and Alexander 1988;Zaidi, Stucki, and Alexander 1988 (Alexander 1965); the physiological capabilities of the microbial communities present in the aquifer, groundwater, or vadose zone ; the interactions of mixtures of chemicals present (Scow, Schmidt, and Alexander 1989); the toxicity of the target contaminant ; and the length of adaptation periods required for degradation to be initiated (Aelion, Swindoll, and Pfaender 1987). (Alexander 1965(Alexander , 1971 (Spain and Van Veld 1983).…”

mentioning

confidence: 99%

“…This leads to a requiremeuL to understand those environmental factors affecting activity or influencing the isolates that can grow rapidly at low substrate levels (Zaidi, Murakami, and Alexander 1988). The inoculated microorganism will also do poorly if there is no carbon source available or if the carbon source is only marginally suitable (Brunner, Sutherland, and Focht 1985).…”

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confidence: 99%

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