Disruption of a fungal organism, Rhizopus nigricans, in a high-pressure homogenizer

The effect of homogeniser impact distance on the disruption of Escherichia coli

“…Results also agree qualitatively with those of Keshavarz-Moore et al (1990). To compare results quantitatively with those of equation (2), conditions used in .this study (Y = valve outer radius = 0.00425 m, r. = valve inner radius = 0.00385 m, p = fluid viscosity = 0.0012 Pa.s, Q = homogeniser flowrate = 4.6x10-5 m%-1 and p = fluid density = 1000 kgm-3) and a Bernoulli-type expression (Phipps, 1975) were used to determine valve gap, h, as a function of operating pressure, P, giving equation (5) (3), and using values in Table 1 gives equation (6).…”

“…High-pressure homogenisation is commonly used in commercial cell-disruption processes, particularly for non-filamentous organisms such as E. coli (Hopkins, 1991). The importance of impingement as a dominant mechanism in the disruption of Saccharomyces cerevisiae in a high-pressure homogeniser has been verified (Keshavarz Moore et al, 1990;Kleinig and Middelberg, 1994). No study of the effect of impact distance on disruption in a high-pressure homogeniser has been reported for E. coli.…”

“…Further studies show that a and k are system and microorganism specific, and depend on the history of the culture (Gray et al, 1972;Sauer et al, 1989;Middelberg et al, 1992a). Keshavarz-Moore et al (1990) examined the effect of homogeniser impact ring diameter and valve seat geometry on yeast disruption efficiency during high-pressure homogenisation. The pressure-dependent rate constant K (equation (1)) was correlated with impact distance, Y, and valve gap, Iz, by replacing the circular orifice diameter with homogeniser-valve gap in equations for an impinging jet, giving equation (2).…”

Significance of location of enzymes on their release during microbial cell disruption

“…Hence, there was no appreciable difference in the values of location factor obtained with different techniques indicating that these two techniques used for the disruption are similar in terms of their disruption intensity as far as the release rate of cytoplasmic enzyme is con- cerned. The value of location factor as approximately 0.5 (<1.0) obtained with both the techniques suggests cytoplasmic location for ADH con®rming the reports by Follows et al (1971) and Keshavarz et al (1990).…”

Application of Cavitational reactors for cell disruption for recovery of intracellular enzymes

“…45,47 Heating the cell suspension as a pre-treatment strategy for translocation of the enzyme was found to be effective for the ADH enzyme. 48 Even the time of culture in the fermentation process was found to affect the location factor of the enzyme.…”