Bead milling, cell disruption

Rotor Bead Mills. Larger-capacity laboratory bead mill cell disrupters agitate the beads with a rotor rather than by shaking. Equipped with efficient cooling jackets, larger sample volumes can be processed without over-... 

Baker s yeast suspension (20% ww/v original cells) was pumped to the bead mill at a flow rate of 280 cm h 1 within the BRG 4.5 cm inner diameter contactor. Then, the disruptate from the mill was directly introduced to the pre-equilibrated fluidised bed containing ZSA II-CB and Macrosorb K4AX-CB. 

The primary purification of the enzyme G3PDH was exploited herein as a preliminary study to investigate and demonstrate the feasibility of the integrated operation of cell disruption by bead milling and immediate product capture by fluidised bed adsorption (panel A in Figure 17.6). Yeast G3PDH binds nicotinamide adenine dinucleotide (NAD) as a cofactor,... 

Experiments investigated the integration of cell disruption by bead milling and product capmre by fluidised bed adsorption. By using fluidised bed adsorption, the clarification of the broth would be incorporated with the capture of the product which would result in a considerably... 

Recovery. The principal purpose of recovery is to remove nonproteinaceous material from the enzyme preparation. Enzyme yields vary, sometimes exceeding 75%. Most industrial enzymes are secreted by a microorganism, and the first recovery step is often the removal of whole cells and other particulate matter (19) by centrifugation (20) or filtration (21). In the case of cell-bound enzymes, the harvested cells can be used as is or disrupted by physical (eg, bead mills, high pressure homogenizer) and/or chemical (eg, solvent, deteigent, lysozyme [9001-63-2], or other lytic enzyme) techniques (22). Enzymes can be extracted from disrupted microbial cells, and ground animal (trypsin) or plant (papain) material by dilute salt solutions or aqueous two-phase systems (23). 

Physical Methods Physical methods include mechanical disruption by milling, homogenization, or ultrasonication. Typical high-speed bead mills are composed of a grinding chamber filled with glass or steel beads which are agitated with disks or impellers mounted on a motor-driven shaft. The efficiency of cell disruption in a bead mill depends on the concentration of the cells, the amount and size of beads, and the type and rotation speed of the agitator. The optimum wet solid content for the cell suspension for a bead mill is typically somewhere between 30 percent to 60 percent by volume. The amount of beads in the chamber is 70 percent to 90 percent by... 

Method of cell disruption yeast suspension 50% wet weight is passed through a bead mill using 0.5 mm glass beads... 

Intracellular Products. Intracellular production of bioproducts is less preferable but sometimes the only way to produce certain compounds in appreciable amounts. In this case, cell disruption is required for recovery. High-pressure homogenization, bead mills, and chemical or enzymatic disruption of the cell wall with lysozyme or similar enzymes can be used to achieve cell breakage. In the case of small molecules, organic solvent extraction has also been described. If cell debris remains in the centrate, it must be removed by methods described above, thus adding extra steps to the process. 

Cell disruption Bead mills High-pressure homogenization Ultrasonication... 

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