◆ Experiment 1 : Influence of light to one meal worm
In order to understand the ideal state for the meal worms, our team measured several conditions that could affect the growth rate of the meal worms. One of them is "light". To measure the effect of light to the mealworms, we set several initial conditions.
-Meal worms are in transparent container of its area of base (20X13)cm^2
-Meal worms' size in average was (2X0.2)cm^2
-Experiment period : 5/20(Fri)~7/01 (measured every Friday)
-Meal worms are eating only polystyrene(4.00g)
-One container is put in shade, another in light
-Meal worms become imagoes faster in light than in shade
◆ Experiment 2 : Duration of survival of the meal worms only relying on polystrene
In order to use the mealworm as a mean of degrading polystrene, our team needed to ensure the survival ability of mealworms relying on polystrene. To measure the possible duration of its survival, we conducted this experiment. There were 5 initial conditions.
-Meal worms are in transparent contain of its area of base 0000cm^2
-Meal worms's size in average was (2.6X0.4)cm^2
-Experiment period : 7/01(Fri)~ (measured once in two weeks)
-Meal worms are put in shade
-Meal worms are eating only polystyrene
-Imago cannot survive depending only on polystyrene
-Imagoes reproduced, and we could find about 40 larvae that were newly born
(there may be more since we couldn't separate the larvae of less than 7mm from excreta)
-Newly born larvae were gathered and grown in another transparent container in sawdust
◆ Experiment 3 : Decomposition Rate of Polystyrene by Mealworms
To further understand the current polystyrene decomposition rate of the meal worms, we implemented several initial conditions.
-Group A and B each has 10 meal worms in their container
-Meal worms in Group A, B are fed only on polystyrene
-Group C has only polystyrene in its container
-Group A and C experiment started in 8/24
-Group B experiment started in 8/25
-The average decomposition rate of polystyrene by mealworms can be drew by the formula
-The amount of polystyrene that one meal worm eats for day
-The average amount of polystyrene that one meal eats for the duration of (31 days)
Adding the PET degradation ability to the meal worms
: Recombination of DH+a and pBBRMCS2-Pcon-yfaL-PETase
The e-coli bacteria, DH+alpha, which is already located inside the mealworm's gut has the ability to decompose polystryene. Our team is trying to recombine DH+alpha and pBBRMCS2-Pcon-yfaL-PETase by chemical transforming them. pBBRMCS2-Pcon-yfaL-PETase is one of a series of plasmid cloning vectors created by Joachim Messing and co-workers. From this experiment we are trying to further the mealworm’s ability to decompose plastic.
Measurement of mealworms (Weight and length)
After feeding 40 mealworms with only plastic for 5 weeks, we measured the length and the weight of the 20 samples. The average weight is 0.177g per worm and the original length is about 30.4cm. Compared to the original length 20.2cm, it is noticeable that mealworms are possible to continue their lives with plastics as their only source of nutrient.
Future plans for the project
After this project of adding the PET degradation ability of mealworms, we have planned several future projects that could continue our previous one. We can synthesize the mealworm’s gut bacteria itself with PETase DNA. Then, we should modify these bacteria to allow it to survive not only in the mealworm’s gut, but also in natural environments.
Using LIC (Ligation Independent Cloning), we cloned PETase, which is an enzyme that breaks down plastic, to plasmid vector. The process of cloning it is finished; however, our experiment is in the process of verifying our results.