The lysis of Gram-negative Alcaligenes eutrophus by enzymes from Cytophaga

Harrison, Susan T.L.; Chase, Howard A.; Dennis, John S.

doi:10.1007/bf00159982

Cited by 8 publications

(6 citation statements)

References 6 publications

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“…System variables affecting homogenizer disruption efficiency include suspension temperature, homogenizer operating pressure, number of homogenizer passes (Hetherington et al, 1971), and homogenizer valve design (Keshavarz-Moore et al, 1990). Cell concentration is reported to have no discernible influence on cell-disruption efficiency over a wide range of cell-concentrations and operating pressures (Hetherington et al, 1971;Brookman, 1974;Btischelberger and Loncin, 1989;Agerkvist and Enfors, 1990;Harrison et al, 1991), with few studies contradicting this (Sauer et al, 1989;Middelberg et al, 199 1).…”

Section: Introductionmentioning

confidence: 96%

Influence of broth dilution on the disruption of Escherichia coli

et al. 1995

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The effect of cell concentration (5 to 150 g/L wet wt after broth dilution) on homogenizer disruption efficiency and homogenate viscosity is reported for E. cob. Broth dilution increases homogenizer efficiency and decreases feed and homogenate viscosity. However, this increase in disruption efficiency is not sufficient to warrant dilution of the broth prior to homogenization. The optimal feed concentration is the maximum possible that does not lead to practical handling difficulties due to high viscosity. INTRODUCTIONHigh-pressure homogenization is a widely used method for mechanical celldisruption on a process scale. System variables affecting homogenizer disruption efficiency include suspension temperature, homogenizer operating pressure, number of homogenizer passes (Hetherington et al., 1971), and homogenizer valve design (Keshavarz-Moore et al., 1990). Cell concentration is reported to have no discernible influence on cell-disruption efficiency over a wide range of cell-concentrations and operating pressures (Hetherington et al., 1971;Brookman, 1974;Btischelberger and Loncin, 1989;Agerkvist and Enfors, 1990;Harrison et al., 1991), with few studies contradicting this (Sauer et al., 1989; Middelberg et al., 199 1).It is surprising that disruption efficiency is reported to be independent of cell concentration. Increased cell concentration raises homogenate viscosity (Agerkvist and Enfors, 1990; Harrison et al., 199 1) and is expected also to increase initial feed viscosity. This higher feed viscosity will cause homogenizer valve gap to increase (Phipps, 1975) leading to a decrease in disruption efficiency (Keshavarz-Moore et al., 1990).This study examines the influence of feed broth dilution on disruption efficiency and homogenate rheology for E. coli, and discusses the practical significance of the results.

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Section: Introductionmentioning

confidence: 96%

Influence of broth dilution on the disruption of Escherichia coli

et al. 1995

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“…The grinding process generates heat which is counter balanced by circulating cooling water surrounding the chamber. Although the alkaline pretreatment of cells containing PHA granules enhances single-pass disruption in a high-pressure homogenizer, full protein release requires at least two passes [ 108 ]. To improve single-pass disruption, substances such as 0.1% SDS, sodium chloride, potassium chloride, lysozyme, EDTA, or mixtures of these can be employed [ 109 ].…”

Section: Extraction Of Phamentioning

confidence: 99%

The Synthesis, Characterization and Applications of Polyhydroxyalkanoates (PHAs) and PHA-Based Nanoparticles

et al. 2021

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Polyhydroxyalkanoates (PHAs) are storage granules found in bacteria that are essentially hydroxy fatty acid polyesters. PHA molecules appear in variety of structures, and amongst all types of PHAs, polyhydroxybutyrate (PHB) is used in versatile fields as it is a biodegradable, biocompatible, and ecologically safe thermoplastic. The unique physicochemical characteristics of these PHAs have made them applicable in nanotechnology, tissue engineering, and other biomedical applications. In this review, the optimization, extraction, and characterization of PHAs are described. Their production and application in nanotechnology are also portrayed in this review, and the precise and various production methods of PHA-based nanoparticles, such as emulsion solvent diffusion, nanoprecipitation, and dialysis are discussed. The characterization techniques such as UV-Vis, FTIR, SEM, Zeta Potential, and XRD are also elaborated.

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“…Pretreatments with lysozyme, EDTA, and combination of the two, were seen to improve single pass disruption relative to untreated material (Harrison et al, 1991c). In further work with enzymes, Harrison et al (1991a) reported essentially complete lysis of A. eutrophus cells upon treatment (37.5°C, pH 7.3, 60 min) with lytic enzymes of Cytophaga sp without any mechanical processing. But lytic enzymes (e.g., hen lysozyme) are generally too expensive for commercial scale processing.…”

Section: Reviewmentioning

confidence: 99%

Optimization of poly(β-hydroxybutyric acid) recovery from Alcaligenes latus: combined mechanical and chemical treatments

Tamer

Moo‐Young

Chisti³

1998

Bioprocess Engineering

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Recovery of the intracellular bioplastic poly(b-hydroxybutyric acid) or PHB from fed-batch cultured Alcaligenes latus, ATCC 29713, was examined using combinations of chemical and mechanical treatments to disrupt the cells. Chemical pretreatments used sodium chloride and sodium hydroxide. For salt pretreatment the cells were exposed to NaCl (8 kg m A3 ) and heat (60°C, 1 h), cooled to 4°C, and mechanically disrupted. For alkaline treatments, the cells were exposed to sodium hydroxide (0.025±0.8 kg NaOH per kg biomass) and mechanically disrupted at ambient temperature. A combined treatment with sodium chloride (8 kg m A3 ), heat (60°C, 1 h), and alkaline pH shock (pH 11.5, 1 min) was also tested. Mechanical disruption employed a continuous¯ow bead mill (2,800 rpm agitation speed, 90 ml min A1 slurry¯ow rate, 512 lm mean bead diameter, bead loadings of 80% or 85% of chamber volume). Disruption was quanti®ed by protein release. Over most of the disruption period, the release of PHB was approximately proportional to protein release. Regardless of the pretreatment or bead load, the disruption obeyed ®rst order kinetics; hence, the rate of protein release was directly proportional to the amount of unreleased protein. Relative to untreated biomass, pretreatment always produced earlier protein release during milling. Pretreatment with a minimum of 0.12 kg NaOH per kg biomass was necessary to enable complete disruption within three passes (85% bead load). Untreated biomass required more than twice as many passes. Irrespective of the chemical pretreatment, the bead loading strongly in¯uenced the disruption rate which was higher at the higher loading. Alkaline hydrolysis associated PHB loss was observed, but it could be limited to insigni®cant levels by immediate neutralization of disrupted homogenates. List of symbolsC NaOH mass ratio of alkali-to-biomass EDTA ethylenediaminetetraacetic acid F¯ow rate of the cell slurry, ml min A1 or m 3 s A1 f ef®ciency factor I electric current, A k disruption rate constant, min A1 N number of passes through bead mill NTU nephelometric turbidity units PHA poly(hydroxyalkanoic acid) PHB poly(b-hydroxybutyric acid) R speci®c protein release after N passes, m A3 R m maximum amount of releasable protein per unit biomass, m A3 R p mass ratio of PHB-to-pellet R s speci®c protein release, g protein kg A1 biomass S slope of lnR m aR m À R versus N plots SDS sodium dodecyl sulfate V volume of the milling chamber, mlGreek symbols a constant in Eq. (5) b constant in Eq. (5), kg g A1 / volume fraction of the beads in the milling chamber m voltage, V n energy input, J m A3

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The lysis of Gram-negative Alcaligenes eutrophus by enzymes from Cytophaga

Cited by 8 publications

References 6 publications

Influence of broth dilution on the disruption of Escherichia coli

Influence of broth dilution on the disruption of Escherichia coli

The Synthesis, Characterization and Applications of Polyhydroxyalkanoates (PHAs) and PHA-Based Nanoparticles

Optimization of poly(β-hydroxybutyric acid) recovery from Alcaligenes latus: combined mechanical and chemical treatments

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