Therefore, knowing this, I can predict that as the lactose is passed over the lactase enzyme, glucose content increases.
SAFETY: The products from the column should not be tasted. Lactase is a relatively safe enzyme, but contact with or inhalation of the enzyme should be avoided to avoid allergic reaction or sensitisation.
METHOD: The first process of involved making the whey. 10cm3 milk was placed in a small beaker, and 3-4 drops of rennet were added. This solution was then stirred and placed in an incubator at 37°c. This was left for 10-15 minutes to curdle. Once this milk had curdled, it was poured into a tea strainer over a beaker, and was gently turned over repeatedly to release the whey from the curd. This whey was separated from the curd, and was placed in a beaker.
The next process involved was immobilising the lactase. 2cm3 lactase was mixed with 8cm3 alginate gel solution. This solution was stirred gently using a glass rod. Then, 20cm3 calcium chloride solution was poured into a clean beaker. Above this, was clamped a 10cm3 syringe barrel. The gel beads were to be left in the calcium chloride solution for 10 minutes to harden, then strained with a tea strainer and rinsed with distilled water.
The final step involved in making a column of immobilised lactase. Here, a syringe barrel was clamped above a small beaker, and a small piece of nylon gauze was placed in the bottom of the syringe. A short length of rubber tubing was attached to the syringe outlet, and a Hoffman clip was screwed on to seal the end of the syringe. This clip can be used to control the flow of liquid from the syringe. The beads were then pored into the syringe barrel.
It was now time to pour the whey into the column to run through the beads of immobilised lactase and collect in the beaker. This is where hydrolysis takes place.
A glucose test strip was used to see how much glucose content had entered our final solution.
RESULTS:
CONCLUSION: The results show that whey does not contain any traces of glucose content, as is the same with milk.
However, once this whey is passed over the immobilised enzyme, the end solution contains 1% glucose content. This is simply because hydrolysis of lactose produces glucose, as well as galactose. The enzyme lactase can be used to hydrolyse lactose. This process is known in uses such as in the production of ice cream and sweetened, flavoured, condensed milk.
EVALUATION: The results showed my hypothesis to be correct. When whey is passed over an immobilised enzyme, glucose content is produced along with the end solution.
However, there were certain factors that affected the results of this experiment. The experiment involved a lot of measuring out substances in beakers. The error, which could have occurred here, is that I can only read to accuracy of the nearest millimetre. This affected the results, as the substances were not fully measured to the absolute correct amount. An improvement to this would be to measure out solutions by weighing in future.
Another source of error would have occurred during separation of the whey and the curd after heating in the incubator. Here, separation may not have fully taken place. Small amounts, which could not be spotted, may have stayed the whey. This would affect the final results as when the lactose would be passed over the lactase, small amounts of the curd may interrupt and affect hydrolysis. This would result in the lactose being broken down less, and therefore less amounts of glucose content would be produced. To overcome this problem, the milk that has become curdled could be placed into a tea strainer over a beaker, not only once, but repeated several times to increase the probability that the two substances have fully separated.
Another factor affecting the results of the experiment would be the amount of times the lactose is passed over the lactase. If lactose is passed over the lactase only once, then it may not have been fully hydrolysed. This is a mistake I made. In order to ensure that it has been fully broken down, it could be passed over the lactase a number of times. This way, the glucose content could be increased as hydrolysis of lactose yields glucose. In other words, as hydrolysis of lactose increases, so does the glucose content. This is another way of improving my results.
This process of passing lactose over lactase several times to increase hydrolysis of lactose could be used in factories to increase glucose content, and to save money.
