1. All solutions must be made up using distilled or deionised water (calcium ions in tap water
    will cause the sodium alginate to set).
 

2. Sodium alginate is not readily soluble, and requires both warm water and stirring to dissolve
    it. Have patience, it will dissolve!
 

3. Immobilize the enzyme by mixing it first with the sodium alginate solution, then adding it a
    drop at a time from the syringe to the calcium chloride solution. Do not allow the tip of the
    syringe to come into contact with the calcium chloride solution. The beads, which contain
    the enzyme immobilized in a matrix of calcium alginate, should be allowed to harden for a
    few minutes before separating them from the liquid with the tea strainer.
 

4. The accompanying figure shows how to set up the immobilised enzyme column using a
    syringe barrel. It is important to use a small piece of nylon gauze inside the barrel, as the
    beads are just the right size to block the syringe outlet.
 

5. Glucose may be detected in the whey leaving the column after a few minutes using the
    glucose test strips.
 
 
 
 

Safety

 
  This practical work may be carried out in a food preparation area if clean equipment
  reserved exclusively for food use is employed. In such circumstances, the liquid leaving the
  column may be tasted if food grade reagents have been used. (Novo Nordisk Lactozym is a
  food-grade enzyme.)

   Lactase is a relatively safe enzyme (it is produced naturally by babies to digest their mother
   milk). However, unnecessary contact with the enzyme or inhalation of dust from
   dried-up enzyme spills should be avoided. In case of spillage or contact with the eyes,
   rinse by flushing with water.