The use of various substrates and substrate concentrations by a Hyphomicrobium sp. isolated from soil: Effect on growth rate and growth yield

Aa, K.; Olsen, Rolf A.

doi:10.1007/bf00175076

Cited by 8 publications

(5 citation statements)

References 15 publications

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“…Furthermore, these two bacteria have the capacity to oxidize carbon monoxide through carbon monoxide dehydrogenase . Members of Hyphomicrobium are able to use organic matter as a carbon source . Their enrichment in the 13 C-heavy fractions suggested that Hyphomicrobium may use either inorganic or organic carbon sources for growth.…”

Section: Discussionmentioning

confidence: 99%

“…53 Members of Hyphomicrobium are able to use organic matter as a carbon sources. 54 Their enrichment in the 13 C-heavy fractions suggested that Hyphomicrobium may use either inorganic or organic carbon sources for growth. In treatments with As(III), unclassified Phycisphaerales and Opitutaceae were enriched in the 13 C-heavy fractions.…”

Section: Carbon Fixation During Microaerophilic Microbial Fe(ii) Oxidationmentioning

confidence: 99%

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Microaerophilic Oxidation of Fe(II) Coupled with Simultaneous Carbon Fixation and As(III) Oxidation and Sequestration in Karstic Paddy Soil

Tong

Zheng

et al. 2021

Environ. Sci. Technol.

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Microaerophilic Fe(II)-oxidizing bacteria are often chemolithoautotrophs, and the Fe(III) (oxyhydr)oxides they form could immobilize arsenic (As). If such microbes are active in karstic paddy soils, their activity would help increase soil organic carbon and mitigate As contamination. We therefore used gel-stabilized gradient systems to cultivate microaerophilic Fe(II)-oxidizing bacteria from karstic paddy soil to investigate their capacity for Fe(II) oxidation, carbon fixation, and As sequestration. Stable isotope probing (SIP) demonstrated the assimilation of inorganic carbon at a maximum rate of 8.02 mmol C m -2 d -1 . Sequencing revealed that Bradyrhizobium, Cupriavidus, Hyphomicrobium, Kaistobacter, Mesorhizobium, Rhizobium, unclassified Phycisphaerales, and unclassified Opitutaceas, were fixing carbon. Fe(II) oxidation produced Fe(III) (oxyhydr)oxides, which can absorb and/or co-precipitate As. Adding As(III) decreased the diversity of functional bacteria involved in carbon fixation, the relative abundance of predicted carbon fixation genes, and the amount of carbon fixed. Although the rate of Fe(II) oxidation was also lower in the presence of As(III), over 90% of the As(III) was sequestered after oxidation. The potential for microbially mediated As(III) oxidation was revealed by the presence of arsenite oxidase gene (aioA), denoting the potential of the Fe(II) oxidizing and autotrophic microbial community to also oxidize As(III). The results of this study demonstrate that carbon fixation coupled to Fe(II) oxidation can increase the carbon content in soils by microaerophilic Fe(II)-oxidizing bacteria, as well as accelerate As(III) oxidation and sequester it in association with Fe(III) (oxyhydr)oxides.

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Section: Discussionmentioning

confidence: 99%

Section: Carbon Fixation During Microaerophilic Microbial Fe(ii) Oxidationmentioning

confidence: 99%

Microaerophilic Oxidation of Fe(II) Coupled with Simultaneous Carbon Fixation and As(III) Oxidation and Sequestration in Karstic Paddy Soil

Tong

Zheng

et al. 2021

Environ. Sci. Technol.

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“…In fact, it can be assumed that growth experiments that were conducted in glassware and mineral medium prepared according to standard laboratory procedures may have contained up to 1 mg liter Ϫ1 of contaminating AOC as the extent of growth in negative controls could not be distinguished from growth in experiments conducted with up to 1 mg liter Ϫ1 of substrate (12,16,17). In effect, this implies that any biodegradation assay conducted at low substrate concentrations (below approximately 1 mg liter Ϫ1 ) is a mixed-substrate assay, which will inevitably have profound effects on both substrate utilization kinetics (18)(19)(20) and yield measurements (12,21). Therefore, experiments designed to quantify substrate utilization kinetics and microbial growth yields at low substrate concentrations should include appropriate measures to minimize the interfering effects of contaminating AOC.…”

mentioning

confidence: 99%

Kinetics and Yields of Pesticide Biodegradation at Low Substrate Concentrations and under Conditions Restricting Assimilable Organic Carbon

Helbling

Hammes

Egli

et al. 2014

Appl Environ Microbiol

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The fundamentals of growth-linked biodegradation occurring at low substrate concentrations are poorly understood. Substrate utilization kinetics and microbial growth yields are two critically important process parameters that can be influenced by low substrate concentrations. Standard biodegradation tests aimed at measuring these parameters generally ignore the ubiquitous occurrence of assimilable organic carbon (AOC) in experimental systems which can be present at concentrations exceeding the concentration of the target substrate. The occurrence of AOC effectively makes biodegradation assays conducted at low substrate concentrations mixed-substrate assays, which can have profound effects on observed substrate utilization kinetics and microbial growth yields. In this work, we introduce a novel methodology for investigating biodegradation at low concentrations by restricting AOC in our experiments. We modified an existing method designed to measure trace concentrations of AOC in water samples and applied it to systems in which pure bacterial strains were growing on pesticide substrates between 0.01 and 50 mg liter ؊1 . We simultaneously measured substrate concentrations by means of high-performance liquid chromatography with UV detection (HPLC-UV) or mass spectrometry (MS) and cell densities by means of flow cytometry. Our data demonstrate that substrate utilization kinetic parameters estimated from high-concentration experiments can be used to predict substrate utilization at low concentrations under AOC-restricted conditions. Further, restricting AOC in our experiments enabled accurate and direct measurement of microbial growth yields at environmentally relevant concentrations for the first time. These are critical measurements for evaluating the degradation potential of natural or engineered remediation systems. Our work provides novel insights into the kinetics of biodegradation processes and growth yields at low substrate concentrations.

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“…However, measurements of YC in the laboratory have sometimes been overestimated, especially when the concentration of the chemical of concern was low, because microorganisms utilized not only the chemical of concern but also uncharacterized organic compounds contaminating the inorganic medium from water, glassware, or air (1,4,6,14,20). Therefore, the YC that was observed reflected the combined influence of the chemicals of concern and uncharacterized organic compounds, rather than the YC of the chemicals alone (1,14,20).…”

mentioning

confidence: 99%

“…One possible explanation is that different degradation systems are involved in the DCP degradation, as a number of studies have reported (1,22). Another hypothesis, such as the effect of maintenance loss (2,23) to allow DP-4 to increase to a density of 10 5 cells ml Ϫ1 when 0.1 g of DCP-C ml Ϫ1 was added.…”

mentioning

confidence: 99%

Estimation of the Yield Coefficient of Pseudomonas sp. Strain DP-4 with a Low Substrate (2,4-Dichlorophenol [DCP]) Concentration in a Mineral Medium from Which Uncharacterized Organic Compounds Were Eliminated by a Non-DCP-Degrading Organism

Tarao

Seto

2000

Appl Environ Microbiol

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The yield coefficient (YC) of Pseudomonas sp. strain DP-4, a 2,4-dichlorophenol (DCP)-degrading organism, was estimated from the number of CFU produced at the expense of 1 unit amount of DCP at low concentrations. At a low concentration of DCP, the YC can be overestimated in pure culture, because DP-4 assimilated not only DCP but also uncharacterized organic compounds contaminating a mineral salt medium. The concentration of these uncharacterized organic compounds was nutritionally equivalent to 0.7 g of DCP-C ml ؊1 . A mixed culture with non-DCP-degrading organisms resulted in elimination of ca. 99.9% of the uncharacterized organic compounds, and then DP-4 assimilated only DCP as a substrate. In a mixed culture, DP-4 degraded an initial concentration of 0.1 to 10 g of C ml of DCP ؊1 and the number of CFU of DP-4 increased. In the mixed culture, DCP at an initial concentration of 0.07 g of C ml ؊1 was degraded. However, the number of CFU of DP-4 did not increase. DCP at an extremely low initial concentration of 0.01 g of C ml ؊1 was not degraded in mixed culture even by a high density, 10 5 CFU ml ؊1, of DP-4. When glucose was added to this mixed culture to a final concentration of 1 g of C ml ؊1 , the initial concentration of 0.01 g of C ml of DCP ؊1 was degraded. These results suggested that DP-4 required cosubstrates to degrade DCP at an extremely low initial concentration of 0.01 g of C ml ؊1 . The YCs of DP-4 at the expense of DCP alone decreased discontinuously with the decrease of the initial concentration of DCP, i.e., 1.5, 0.19, or 0 CFU per pg of DCP-C when 0.7 to 10, 0.1 to 0.5, or 0.07 g of C ml of DCP ؊1 was degraded, respectively. In this study, we developed a new method to eliminate uncharacterized organic compounds, and we estimated the YC of DP-4 at the expense of DCP as a sole source of carbon.

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The use of various substrates and substrate concentrations by a Hyphomicrobium sp. isolated from soil: Effect on growth rate and growth yield

Cited by 8 publications

References 15 publications

Microaerophilic Oxidation of Fe(II) Coupled with Simultaneous Carbon Fixation and As(III) Oxidation and Sequestration in Karstic Paddy Soil

Microaerophilic Oxidation of Fe(II) Coupled with Simultaneous Carbon Fixation and As(III) Oxidation and Sequestration in Karstic Paddy Soil

Kinetics and Yields of Pesticide Biodegradation at Low Substrate Concentrations and under Conditions Restricting Assimilable Organic Carbon

Estimation of the Yield Coefficient of Pseudomonas sp. Strain DP-4 with a Low Substrate (2,4-Dichlorophenol [DCP]) Concentration in a Mineral Medium from Which Uncharacterized Organic Compounds Were Eliminated by a Non-DCP-Degrading Organism

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