Disruption of Neisseria denitrificans cells by microfluidizer was optimized using a factorial experiments design. The pH, pretreatment time, cell concentration, NaCl, ethylenediamine tetraacetic acid (EDTA) and Triton X-100 concentrations showed significant impact on disruption process and the process was optimized using central composite design and response surface methodology (RSM). Investigation revealed optimum conditions: 90 min pretreatment at pH 9.0 containing 110 g L(-1) cells (dry cell weight), 50 mM NaCl, 10 mM EDTA, and 0.2% Triton X-100. At optimized conditions, the disruption rate increased twofold, up to 5.62 ± 0.27 × 10(-3) MPa(-a); meanwhile, yield of intracellular content was increased by 26%, with 1 g of cells resulting in 113.2 ± 8.2 mg proteins, 12.1 ± 0.7 mg nucleic acids, 21.0 ± 1.2 mg polysaccharides, 0.99 ± 0.08 kU glucose-6-phosphate dehydrogenase (G6PD), and 10,100 ± 110 kU restriction endonuclease NdeI endonuclease. Particle size distribution analysis revealed nearly twofold larger cell lysate particles with diameter of 120 nm. For optimal release of intracellular content, 9200 J/g of energy was needed (95% confidence), yielding 6900 J/g energy savings. Model equations generated from RSM on cell disruption of N. denitrificans were found adequate to determine significant factors and its interaction. The results showed that optimized combination of known pretreatment and disruption methods could considerably improve cell disruption efficiency.
Influence of various conditions on crossflow microfiltration of disrupted Arthrobacter luteus cells has been analyzed. Evaluation of permeate flux and transmission of macromolecules through the membrane demonstrates that the 750 kDa MWCO polysulfone membrane is the most efficient. Ionic strength, cell concentration, and pH have the highest influence on the yield of AluI restriction endonuclease. Meanwhile, the flocculation and decreased pH have the largest effect on performance of crossflow microfiltration. Flocculation with polyethyleneimine (PEI) have increased the permeate flux to 45.7 Lh −1 m −2 and pH5.5 decreased the flux to 22.2 Lh −1 m −2 . In conclusion, optimal conditions for crossflow microfiltration of A. luteus cells lysate have been identified.
Darbe nagrinėti rutulinių ir lazdelinių formų bakterijų ardymo mechaniniais metodais dėsningumai. Nustatyta, jog rutulinės formos bakterijos lengviau suardomos ultragarsu bei tradicinės konstrukcijos didelio slėgio homogenizatoriumi. Tuo tarpu dėl geometrinės formos lazdelinės bakterijos lengviau suardomos rutuliniu malūnu. Energijos sąnaudų bei ardymo greičio atžvilgiu universaliausias abiejų tipų ląstelių metodas yra ardymas didelio slėgio priešingų srautų konstrukcijos homogenizatoriumi. Ištyrus dalelių dydžio pasiskirstymą, nustatyta, jog rutulinių ir lazdelinių formų bakterijų ardymo mechanizmai skiriasi iš esmės. Rutulinės formos bakterijos yra sumalamos iki smulkių, mikroskopu sunkiai matomų dalelių, tuo tarpu lazdelinės formos bakterijose yra padaromi trūkiai, pakankami, kad viduląsteliniai produktai patektų į aplinką.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.