Device for producing large-sized polymer beads (2 - 4 mm)

Designed by Taylor Morey and Yoav Bashan

Environmental Microbiology Group, Northwestern Center for Biological Research (CIBNOR), La Paz, B.C.S., Mexico

Macrobead-producing device

Entrapment of microorganisms in a polymer matrix was invented three decades ago by the fermentation industry to produce industrial products with microorganisms in fermentation units without losing the microorganisms when the product was harvested.

In 1986, this technology was modified in Israel to produce microbial inoculants of plant growth-promoting bacteria in agriculture. In the mid-1990s, this technology was further modified to entrap (immobilize) microalgae for wastewater treatment. In 2000, the technology was further modified to allow co-immobilization of microalgae and beneficial bacteria for enhanced wastewater treatment. This is an experimental technology in all its modifications, currently used in research laboratories, worldwide. The use of beads is reported in dozens of scientific publications and is a widely accepted tool in the science community.

The main limitation of the technology is the slow rate of bead production because it involves dropping the viscous polymer solution (mostly alginate) through a small opening in a large syringe, a tiring procedure for lab personnel.

This tool was designed to overcome the basic problem of the excessive time and effort to produce large amount of beads. This tool can produce liters of beads (spheres) effortlessly in 10 minutes or less. It is basically a metal shower-head with precisely designed and manufacture apertures.

The main advantages of the macro-bead producing tool are:
  1. Produces liters of beads effortlessly.
  2. Can be easily modified to produce smaller amounts of beads.
  3. Is easily constructed from common materials with common machine shop tools; therefore it is inexpensive.
  4. Will not rust.
  5. Is cleaned with running water.
  6. Can be sterilized for axenic cultures.
  7. Has no moving parts; therefore is free from wear maintenance.
  8. Requires very little training of personnel, about 10 minutes.

A minor inconvenience when large production units are made, the last batch of beads is produced slower than the initial volume.

This website contains a technical specifications and construction of the tool, a technical diagram, a photograph of the device, a PowerPoint presentation of the procedure for rapidly producing large quantities of beads, photographs (in a photo gallery), a PDF file of the publication describing the entire procedure, the device, and its usefulness for biotreatment of wastewater and bacterial inoculant for agriculture, and two PDFs of publications (1, and 2) demonstrating the practical application of these beads as carriers (inoculant) of plant growth-promoting bacteria in the field.

The devices that we routinely use were constructed by Guillermo Garcia-Cortes in the technical workshop of CIBNOR in Mexico.