Team:UNITN-Trento/Project/Home Edition

Home Edition is conceived thinking about what families and regular fruit consumer need: a further way to control fruit ripening at home. There are plenty of occasions in which getting ripe fruit in time is needed, and just as much in which we want our fruit to stay green as long as possible. Home Edition is a reliable, easy to use, paper bag that can speed up or slow down ripening of the fruit that you can find in any family’s kitchen!!

We chose paper as the main material since fruit perspiration would be restricted if the bag was in plastic. The sack is designed to have a little container on the inside called the pocket: it contains two semi-permeable pods with engineered B. subtilis that allow the molecules (in one case ethylene and in the other MeSA) to exit and act on fruit, but at the same time avoid Bacillus to get outside. We went for Bacillus subtilis as our chassis because it forms endospores, so it can be stored in a dormant and safe state. Taking in consideration the marketability of the idea, the capacity to turn into spores seems to be convenient and suitable for Home Edition.

The paper bag is equipped with two different plastic pods that can be placed in the pocket allowing whether ethylene production or MeSA production: both are made of two compartments, one with bacillus spores, and the other (breakable) with nutrient and the respective inducer. The pod is built with a plastic material that allows ethylene/MeSA to escape in the paper bag, but entraps the bacteria inside the pod itself. For this device we took inspiration from groningen 2012 igem team’s “sticker”, a fascinating device that they designed and actually built in order to detect and report volatiles in spoiling meat. After breaking the partition wall between the two chambers, the nutrition goes to the spores reactivating them; the inducer enables the bacteria to produce the molecule demanded, that will go out through this special semi-permeable plastic. Therefore ethylene/ MeSA production is avoided until nutrients and inducer are added. The two different sachets are coloured differently, for an easy-to-use application, one is blue-colored (MeSA) and the other is orange (ethylene).

Once you break the desired compartment, you just put the pod inside the pocket then zip the bag and here we go!!