Measurement of the Growth of a Floc Forming Bacterium Pseudomonas putida CP1

Fakhruddin, A. N. M.; Quilty, Bríd

doi:10.1007/s10532-006-9054-x

Cited by 13 publications

(11 citation statements)

References 38 publications

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“…It was not possible to measure the growth of P. fluorescens after the first 3 days due to the aggregation of cells in the culture medium. Such behavior of cell aggregation and increased hydrophobicity has previously been observed in P. putida CP1 [41, 42] and P. fluorescens [21] when grown under stressful conditions. Due to the reduction in size of cells under these conditions, the increase in cell counts were in disagreement with the cell dry weight and optical density [41].…”

Section: Discussionsupporting

confidence: 59%

RETRACTED ARTICLE: Bacterial conversion of depolymerized Kraft lignin

Ravi

Abdelaziz

Nöbel

et al. 2018

Biotechnol Biofuels

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BackgroundLignin is a potential feedstock for microbial conversion into various chemicals. However, the degradation rate of native or technical lignin is low, and depolymerization is needed to obtain reasonable conversion rates. In the current study, base-catalyzed depolymerization—using NaOH (5 wt%)—of softwood Kraft lignin was conducted in a continuous-flow reactor system at temperatures in the range 190–240 °C and residence times of 1 or 2 min. The ability of growth of nine bacterial strains belonging to the genera Pseudomonas and Rhodococcus was tested using the alkaline-treated lignin as a sole carbon source.ResultsPseudomonas fluorescens and Rhodococcus opacus showed the best growth of the tested species on plates with lignin. Further evaluation of P. fluorescens and R. opacus was made in liquid cultivations with depolymerized lignin (DL) at a concentration of 1 g/L. Size exclusion chromatography (SEC) showed that R. opacus consumed most of the available lower molecular weight compounds (approximately 0.1–0.4 kDa) in the DL, but the weight distribution of larger fractions was almost unaffected. Importantly, the consumed compounds included guaiacol—one of the main monomers in the DL. SEC analysis of P. fluorescens culture broth, in contrast, did not show a large conversion of low molecular weight compounds, and guaiacol remained unconsumed. However, a significant shift in molecular weight distribution towards lower average weights was seen.ConclusionsRhodococcus opacus and P. fluorescens were identified as two potential microbial candidates for the conversion/consumption of base-catalyzed depolymerized lignin, acting on low and high molecular weight lignin fragments, respectively. These findings will be of relevance for designing bioconversion of softwood Kraft lignin.Electronic supplementary materialThe online version of this article (10.1186/s13068-018-1240-7) contains supplementary material, which is available to authorized users.

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Section: Discussionsupporting

confidence: 59%

RETRACTED ARTICLE: Bacterial conversion of depolymerized Kraft lignin

Ravi

Abdelaziz

Nöbel

et al. 2018

Biotechnol Biofuels

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“…From this rate, a doubling time of 9.4 h can be calculated for the strain CECT5344, as it could be expected, higher than doubling times obtained when a cyanate (5 h), ammonium (2.5 h) and nitrate (2.6 h) as used as nitrogen source [38]. A specific growth rate of 0.013 h −1 for a strain (CP1) of Pseudomonas putida in the presence of the pollutant 4-chlorophenol [39], and one of 0.2 d −1 for a strain (KPN) of P. pseudoalcaligenes under optimum conditions and the presence of pyridine as carbon and nitrogen source [40], were obtained in previous work.…”

Section: Resultsmentioning

confidence: 79%

Alkaline cyanide degradation by Pseudomonas pseudoalcaligenes CECT5344 in a batch reactor. Influence of pH

Huertas

Sáez

Roldán

et al. 2010

Journal of Hazardous Materials

109

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“…the growth of bacteria in freely suspended biofilms in flocs, is also a successful strategy used by bacteria to inhabit the pelagic zone of oceans or bodies of fresh water (marine or lake snow) [19], [20], is industrially vital, e.g. in sewage treatment plants (flocculation) [21], [22], and can be a response of bacteria to stressful environmental conditions [23], [24]. It is feasible that planktonic cellular aggregation is mediated by the same mechanisms as those involved in the formation of surface-attached biofilms, and many of the physiological traits exhibited by biofilms have been observed in planktonic cultures [25].…”

Section: Introductionmentioning

confidence: 99%

Pseudomonas aeruginosa PAO1 Preferentially Grows as Aggregates in Liquid Batch Cultures and Disperses upon Starvation

et al. 2009

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In both natural and artificial environments, bacteria predominantly grow in biofilms, and bacteria often disperse from biofilms as freely suspended single-cells. In the present study, the formation and dispersal of planktonic cellular aggregates, or ‘suspended biofilms’, by Pseudomonas aeruginosa in liquid batch cultures were closely examined, and compared to biofilm formation on a matrix of polyester (PE) fibers as solid surface in batch cultures. Plankton samples were analyzed by laser-diffraction particle-size scanning (LDA) and microscopy of aggregates. Interestingly, LDA indicated that up to 90% of the total planktonic biomass consisted of cellular aggregates in the size range of 10–400 µm in diameter during the growth phase, as opposed to individual cells. In cultures with PE surfaces, P. aeruginosa preferred to grow in biofilms, as opposed to planktonicly. However, upon carbon, nitrogen or oxygen limitation, the planktonic aggregates and PE-attached biofilms dispersed into single cells, resulting in an increase in optical density (OD) independent of cellular growth. During growth, planktonic aggregates and PE-attached biofilms contained densely packed viable cells and extracellular DNA (eDNA), and starvation resulted in a loss of viable cells, and an increase in dead cells and eDNA. Furthermore, a release of metabolites and infective bacteriophage into the culture supernatant, and a marked decrease in intracellular concentration of the second messenger cyclic di-GMP, was observed in dispersing cultures. Thus, what traditionally has been described as planktonic, individual cell cultures of P. aeruginosa, are in fact suspended biofilms, and such aggregates have behaviors and responses (e.g. dispersal) similar to surface associated biofilms. In addition, we suggest that this planktonic biofilm model system can provide the basis for a detailed analysis of the synchronized biofilm life cycle of P. aeruginosa.

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Measurement of the Growth of a Floc Forming Bacterium Pseudomonas putida CP1

Cited by 13 publications

References 38 publications

RETRACTED ARTICLE: Bacterial conversion of depolymerized Kraft lignin

RETRACTED ARTICLE: Bacterial conversion of depolymerized Kraft lignin

Alkaline cyanide degradation by Pseudomonas pseudoalcaligenes CECT5344 in a batch reactor. Influence of pH

Pseudomonas aeruginosa PAO1 Preferentially Grows as Aggregates in Liquid Batch Cultures and Disperses upon Starvation

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