Team:Hong Kong UCCKE/Experiments

Experiments


Experiments


Conditions for anaerobic digestion

Before we design a gene for digesting food waste, we ought to find the best conditions for anaerobic digestion to cooperate with the gene and produce the best detergent with the highest digestion rate. Therefore, we performed the following experiments by changing different variables.

To determine the best conditions, we used the help of various parameters:

Dependent Variables

Pressure

The air pressure accumulated is due to the production of gases(CO2,CH4,H2 etc.) in anaerobic digestion, while the rate of gas production is proportional to the rate of anaerobic reaction. It can be used as a parameter to measure the rate of anaerobic digestion.
Expectation:

Reduction in solid mass and total mass

One of our main targets is to reduce the solid mass and the total mass of food waste so that it takes up less space for disposal and ease the landfill shortage problem. So we can measure our progress by measuring the reduction in solid mass and total mass at the end of each experiment. The reduction in mass is due to the breakdown of complex food waste polymers into simpler substrates, the consumption of food substrates by microbes, the fermentation of food substrates by bacteria into liquid and gas, and the dissolution of solid.
Expectation:

Smell

In order to make our device user-friendly in housing estates, we must make sure it gives out no unacceptable smell or pleasant smell. So we regularly record the smell in each experiment and find various ways to improve it.
Expectation:

pH

To make sure the food waste product is in the pH range where enzymes and our designed gene work properly, ensure demonstration of its cleansing property.
Expectation:

Detergent effect

To test the cleansing property of the food waste product, and comparing it in ratio with the cleansing property of water and 1% concentration detergent.
Expectation: To have a cleansing effect better or near 1% concentration detergent.


Experiment 1

Aim: To test if the addition of sugar will affect the rate of respiration

Major considering D.V.: mass reduction


Design

This experiment is designed to test if different food waste can be used to make eco-enzymes and if sugar can increase the rate of respiration. We try to compare which kind of food will adapt a better rate of respiration. The food waste we used are those which commonly seen in meal in Hong Kong. We expected that those with sugar will have higher rate of respiration than those don’t have it.

This experiment’s protocol referenced the commonly used protocol on a website.

Materials

Material (weight) Amount
Water (100g) x10
Rice (30g) x2
Pork (30g) x2
Eggplants (30g) x2
Lettuce (30g) x2
Pork with sauce (30g) x2
Brown sugar (10g) x10
Plastic bottles x10
Pestle and mortar x5
Electrical weight x2
Filter funnel x4
Measure cylinder x2
Scissors x5

Procedure

  1. Label the plastic bottles according to the symbols below
  2. Prepare 100 grams of water, 30 grams of food waste and 10 grams of brown sugar
  3. With the use of water, pestle and mortar, granulate the food waste
  4. By the use of filter funnel and glass rod, pour the water, brown sugar and the granulated food waste into a plastic bottle
  5. Tighten the bottle cap
  6. Release the bottle cap
  7. Record the colour, smell, settlements of the bottle
  8. Repeat step 6 and 7 weekly, last for ~3 months

Labels

Name Meaning With Sugar?
R22 Rice mixture No
R22S Rice mixture Yes
V22 Eggplant mixture No
V22S Eggplant mixture Yes
V22 Lettuce mixture No
V22S Lettuce mixture Yes
Ms22 Pork with sauce mixture No
Ms22S Pork with sauce mixture Yes
M22 Pork without sauce mixture No
M22S Pork without sauce mixture Yes


Experiment 2: Effect of temperature on reaction rate of food waste

Aim: To find out the best condition for the metabolism of enzymes

Major considering D.V.: mass reduction


Design

Considering the convenience of users, we designed experiment 2 to try to lessen the reaction time to 1 month. We attended this experiment to test if raising the temperature of the food waste will increase the rate of reaction. It is expected that higher temperature can effectively increase the rate of respiration.

Material

Material (weight) Amount
Water (100g) x6
Rice (30g) x2
Pork (30g) x2
Lettuce (30g) x2
Brown sugar (10g) x6
Plastic bottles x6
Pestle and mortar x3
Electrical weight x2
Filter funnel x3
Measure cylinder x2
Scissors x3
Incubator x1

Procedure

  1. Label the plastic bottles according to the symbols below
  2. Prepare 100 grams of water, 30 grams of food waste and 10 grams of brown sugar
  3. With the use of water, pestle and mortar, grind the food waste
  4. By the use of filter funnel and glass rod, pour the water, brown sugar and the granulated food waste into a plastic bottle(for 3 bottles)
  5. Tighten the bottle cap
  6. Label the plastic bottles
  7. Release the bottle cap
  8. Record the colour, smell, settlements of the bottle
  9. Put the bottle labeled R37S: V37S: M37S in the incubator(37°C), leave the other R22S:V22S: M22S: at room temperature (22 C)
  10. Repeat step 6 and 7 daily, last for 1 months
  11. Record the pH value of the mixture in the bottle by the use of universal indicator/ pH test paper

Labels

Name Meaning Temperature
R22S Rice mixture (with sugar) 22C
V22S Lettuce mixture (with sugar) 22C
M22S Pork mixture (with sugar) 22C
R37S Rice mixture (with sugar) 37C
V37S Lettuce mixture (with sugar) 37C
M37S Pork mixture (with sugar) 37C


Experiment 3: Effect of yeast on the reaction rate of food waste

Aim: To find out the best condition for the metabolism of enzymes

Major considering D.V.: mass reduction, detergent test

Design

By experiment 2, we know that increasing temperature can increase the rate of reaction. Therefore , we keep the temperature the same as experiment 2 , then we try to add yeast into the food waste and test if it can fasten the rate of respiration. We expected adding yeast will increase the respiration rate .

Material

Material (weight) Amount
Water (100g) x6
Rice (30g) x2
Pork (30g) x2
Lettuce (30g) x2
Brown sugar (10g) x6
Yeast (1g) x3
Plastic bottles x6
Pestle and mortar x3
Electrical weight x2
Filter funnel x3
Measure cylinder x2
Scissors x3

Procedure

  1. Label the plastic bottles according to the symbols below
  2. Prepare 100 grams of water, 30 grams of food waste and 10 grams of brown sugar
  3. With the use of water, pestle and mortar, grind the food waste
  4. By the use of filter funnel and glass rod, pour the water, brown sugar and the granulated food waste into a plastic bottle(for 3 bottles)
  5. Repeat steps 1-3, but also add 1 gram of yeast for the bottles labeled
  6. Tighten the bottle cap
  7. Label the plastic bottles
  8. Release the bottle cap
  9. Record the colour, smell, settlements of the bottle
  10. Put all the finished bottles in the incubator (37°C)
  11. Repeat step 6 and 7 daily, last for 1 months
  12. Record the pH value of the mixture in the bottle by the use of universal indicator/ pH test paper

Labels

Name Meaning With Yeast?
R37SY Rice mixture (with sugar) Yes
V37SY Lettuce mixture (with sugar) Yes
V37SY Pork mixture (with sugar) Yes


Experiment 4: Effect of Kiwi and Pineapple juice to the smell of food waste

Aim: to determine the effect of kiwi and pineapple juice to food waste

Major considering D.V.: Smell, mass reduction

Design

From the smell of the eco-enzymes in experiment 1, we find that the smell of detergents are really bad, therefore we designed experiment 3 to improve the smell of detergents by using some fruits. We chose kiwi and pineapple juice to add in as their smell are not bad and they are natural protease which we think can also improve the rate of reaction of protein.

Protocol (Part a)

Materials

Material (weight) Amount
Water (200g) x6
Rice (30g) x3
Lettuce (30g) x3
Brown sugar (20g) x6
Pineapple Juice (20g) x2
Kiwi Juice (20g) x2
Plastic bottles x6
Electrical weight x2
Filter funnel x2
Food blender x1
Strainer x1

Procedure

Preparation of fruit juice:

  1. Clean the fruit using tap water
  2. Cut the fruit in half and remove the skin using a knife
  3. Cut the fruit into small pieces
  4. Put the pieces of fruit into a food blender
  5. Blend fruit into paste
  6. Strain the paste and collect the juice

Protocol:

  1. Prepare 200 grams of water, 30 grams of food waste and 20 grams of brown sugar for each bottle.
  2. Label the plastic bottles according to the keys
  3. With the use of a food blender, blend the food waste into a paste
  4. By the use of filter funnel and glass rod, pour the water, brown sugar and the granulated food waste into a plastic bottle
  5. Add 20 grams of kiwi juice or pineapple juice (no need for control)
  6. Release the bottle cap
  7. Record the colour, smell, settlements,pressure of the bottle
  8. Tighten the bottle cap
  9. Put it in the incubator and set the temperature as 37°C
  10. Repeat step 6-9 every 2-3 days, last for ~1months

Labels

Name Meaning With Pineapple/Kiwi Juice?
R37S Rice control None
R37SK Rice (with sugar) Kiwi
V37SP Lettuce (with sugar) Pineapple
V37S Lettuce (with sugar) None
V37SK Pork (with sugar) Kiwi
V37SP Pork (with sugar) Pineapple

Protocol (Part b)

Materials

Material (weight) Amount
Water (200g) x6
Meat (30g) x6
Brown sugar (20g) x6
Pineapple Juice (20g) x2
Kiwi Juice (20g) x2
Plastic bottles x6
Electrical weight x2
Filter funnel x2
Food blender x1
Strainer x1

Procedure

  1. Prepare 200 grams of water, 30 grams of food waste and 20 grams of brown sugar for each bottle.
  2. Label the plastic bottles according to the keys
  3. With the use of a food blender, blend the food waste into a paste
  4. By the use of filter funnel and glass rod, pour the water, brown sugar and the granulated food waste into a plastic bottle
  5. Add 20 grams of kiwi juice or pineapple juice (no need for control)
  6. Release the bottle cap
  7. Record the colour, smell, settlements,pressure of the bottle
  8. Tighten the bottle cap
  9. Put it in the incubator and set the temperature as 37°C
  10. Repeat step 6-9 every 2-3 days, last for ~1months

Labels

Name Meaning With Pineapple/Kiwi Juice?
R37S1 Meat control None
R37S2 Meat control None
V37SK1 Meat (with sugar) Kiwi
V37SK2 Meat (with sugar) Kiwi
V37SP1 Meat (with sugar) Pineapple
V37SP2 Meat (with sugar) Pineapple


Experiment 5: Effect of changing the ratio of food waste, sugar and water on the mass reduction of food waste

Aim: To test if the ratio of food waste, sugar and water will affect the rate of producing eco-enzyme

Major considering D.V.: Mass reduction

Design

From the results in experiment 1, we concluded that adding sugar can increase the rate of respiration , therefore we designed this assay to test if adding the amount of sugar will increase the rate of respiration. To test the effect of adding more sugar, we have a control set of experiment and a set of bottles which added double amount of sugar than the control set. Also, we want to test different conditions of food waste , so we increase the amount of water to see if there is any help in the respiration. There is a set of repeat experiment in this experiment, its purpose is to test the weird or wrong data we collected before.

Materials

Material (weight) Amount
Water (100g and 200g) x2 and x8
Rice (30g) x5
Cabbage (30g) x5
Brown sugar (10g and 20g) x6 and x4
Plastic bottles x10
Electrical weight x2
Filter funnel x4
Measuring cylinder x2
Food blender x1

Procedure

  1. Prepare food waste, sugar and water of the amount below:
    Set Food waste Water Sugar
    1 30g rice 10g 100g
    2 30g rice 10g 200g
    3 30g rice 20g 200g
    4 30g cabbage 10g 200g
    5 30g cabbage 20g 200g

  2. Label the plastic bottles with their ratios of water, sugar and food waste
  3. Start with the amount in set 1
  4. With the use of water and food blender, granulate the food waste
  5. By the use of filter funnel and glass rod, pour the water, brown sugar and the granulated food waste into a plastic bottle
  6. Tighten the bottle cap
  7. Repeat step 4 to step 6 with the amount in set 2-5
  8. Repeat step 1-7 to get another set of data
  9. Release the bottle cap
  10. Record the colour, smell, settlements,pressure of the bottle
  11. Put it in the incubator and set the temperature as 37°C
  12. Repeat step 9-11 every 2-3 days, last for ~1months

Labels

Name Meaning Amount of Sugar Amount of Water
R3711a Rice 10g 100g
R3711b Rice 10g 100g
R3712a Rice 10g 200g
R3712b Rice 10g 200g
R3722a Rice 20g 200g
R3722b Rice 20g 200g
V3712a Vegetables 10g 200g
V3712b Vegetables 10g 200g
V3722a Vegetables 20g 200g
V3722b Vegetables 20g 200g


Experiment 6:Effect of Bokashi on the food waste digestion process and smell problem

Aim: To test if Bokashi can increase the reaction rate of the samples and improve the smell of the products

Design

After the interview with Eco-greeny , we find out a chemical called Bokashi has a great help in the traditional fertilisation of food waste and can also improve the smell. Therefore, we carried out this experiment to test if Bokashi can increase the reaction rate of the samples and improve the smell of the products. From research on the websites, we find out that adding water to Bokashi will lead to a bad smell. So we carried out 3 sets of experiment, which is food waste with sugar(control set), Food waste with Bokashi and food waste with Bokashi and water.

Materials

Material (weight) Amount
Water
Rice (30g) x3
Vegetables (30g) x3
Meat (30g) x3
Brown sugar (10g) x3
Bokashi (10g) x6
Plastic bottles x9
Electrical weight x2
Filter funnel x4
Measure cylinder x2
Food blender x1

Procedure

Labels

Name Meaning With Bokashi? With Water?
R37S Rice (at 37C) No No
R37SB Rice (at 37C) Yes No
R37SBW Rice (at 37C) Yes Yes
V37S Vegetables (at 37C) No No
V37SB Vegetables (at 37C) Yes No
V37SBW Vegetables (at 37C) Yes Yes
M37S Meat (at 37C) No No
M37SB Meat (at 37C) Yes No
M37SBW Meat (at 37C) Yes Yes


Experiment 7: Effect of the use of electric blender in preparation on the mass reduction of food waste

Aim: To find out the best condition for the metabolism of enzymes

To test if the use of the electric blender in preparation can greatly increase the rate of food waste digestion


Design

In some experiments, we used the electric blender to help instead of granulating the food waste by our own. It turned out to have a greater reduction in solid mass, therefore we carried out this experiment to test if using blender can really help with the reduction in solid mass.

Material

Material (weight) Amount
Water (100g) x6
Rice (30g) x2
Meat (30g) x2
Lettuce (30g) x2
Brown sugar (20g) x12
Plastic bottles x6
Pestle and mortar x3
Electrical weight x2
Filter funnel x2
Measure cylinder x1
Strainer x1
Food blender x1

Procedure

  1. Label the plastic bottles according to the symbols below
  2. Prepare 100 grams of water, 30 grams of food waste and 10 grams of brown sugar
  3. With the use of water, pestle and mortar, grind the food waste
  4. By the use of filter funnel and glass rod, pour the water, brown sugar and the granulated food waste into a plastic bottle(for 3 bottles)
  5. Repeat steps 1-3, but use food blender instead to blend the food waste for the bottles labeled R37SB, V37SB and M37SB
  6. Tighten the bottle cap
  7. Put all the finished bottles in the incubator(37°C)
  8. Release the bottle cap
  9. Record the colour, smell, settlements of the bottle
  10. Repeat step 8 and 9 daily, last for 1 months

Labels

Name Meaning Temperature
R22S Rice mixture (with sugar) 22C
V22S Lettuce mixture (with sugar) 22C
M22S Pork mixture (with sugar) 22C
R37S Rice mixture (with sugar) 37C
V37S Lettuce mixture (with sugar) 37C
M37S Pork mixture (with sugar) 37C


Tests

Besides the experiments above, we also conducted different tests for the experiments, to test the different performance of eco-enzymes and if the eco-detergents reach the goal we set.


Mass reduction test

Aim

To find out the reduction of solid mass and total mass, as the weight of reduction has direct relationship with the rate of respiration of the eco-enzymes.

Material


Procedure

  1. Take out the bottles from the incubator
  2. Weigh the total mass
  3. Pour the solution into the beaker through the sieve to separate the residue, use a metal spoon to help
  4. Put the residue to the spot plate regularly
  5. Measured the residue with an electronic balance
  6. Measured the liquid with an electronic balance

pH test

Aim

To test the pH value of the samples in the experiments above.

Material

Material (weight) Amount
20-200um pipette x1
100-1000um pipette x2
200-1000um filter tip x20
Universal indicator (40um) x10
The finished eco-detergent (1000um) x10
Test tube x10
Test tube rack x1
1-200um filter tip x10
Water (960um) x10

Procedure

  1. Prepare 40 ul of universal indicator, 960ul water and 1000ul of the finish eco-detergent marked at the top
  2. Put a pipette in a pipette filler, use it to transport 40ul universal indicator to a test tube
  3. Use another pipette filler and pipette to transport 960ul water to the test tube
  4. Use one more pipette filler and pipette to transport 1000ul of the finished eco-detergent to a rest tube
  5. Repeat step 4 until all the finished eco-detergent are mixed with universal indicator and water
  6. Shake the finished test tube gently and put them on a test tube rack
  7. Watch the color change of different eco-detergent
  8. After one month, perform the mass reduction test, pH test, and detergent test

Detergent test

Aim

To test the cleansing property of eco-enzymes.

Design

For the detergent test, we used a ratio named A power as a reference for the sample’s cleansing property. 0 in this ratio equals to the cleaning effect of water, while 1 equals to that of 1% concentrated detergent

Materials

Materials (weight) Amount
Pipette filler x3
5mL pipettes x8
Test tube x7
Oil (5mL) x7
Beaker x1
test tube rack x1
Ruler x1
The finished eco-detergent (5mL) x6
Detergent (5mL) x1

Procedures

  1. Put a pipette in a pipette filler, use it to transport 5mL oil to a test tube
  2. Use another pipette filler and pipette to transport 5mL detergent to the test tube
  3. Label the test tube as positive result(+)
  4. Put positive(+) on the test tube rack and wait for 10 minutes
  5. After 10 minutes, measure the length of the upper part of the positive result in cm
  6. Record the result
  7. Use the same pipette filler with pipette in step 1
  8. Repeat step 1 to 6 but use eco-detergents instead in step 2
  9. Label the test tubes by the labels of the eco-detergents (RC,VC,RP,VP,RK)