Introduction

Bacterial cellulose (BC) exhibits a multitude of different properties depending on the processing, growth conditions, functionalisation and strain used (Bismarck 2013) for production of the material. Acquiring large quantities of cellulose produced would allow testing of a broad variety of cellulose processing methods and functionalisation steps.

By mass producing cellulose this enables a better understanding of what material properties can be realistically produced during the short duration of iGEM. More importantly, it improves the likelihood of finding suitable processing candidates for the project’s aim of making a customisable ultrafiltration membrane, at the same time as allowing room for creativity and exploration of the remarkable properties of cellulose.

Minimum requirements

1. Treatment of BC requires killing the cells, particularly if the cells are genetically engineered, which is the aim for putting the customisable in ultrafiltration membranes.
2. Based on brainstorming with Central Saint Martins student Zuzana, removing the colour of BC is required as it looks displeasing to the eye otherwise, and seems counter-intuituve to filter clean water with cellulose coloured like turbid water.
3. Removal of the smell of BC has also been raised as a requirement, particularly by producers who work in close contact with the processing facilities.

Mass Production Methods

Setting up the mass production of cellulose was done according to the Kombucha media protocol , which involved setting up 61 trays with media and G. xylinus and yeast co-culture as shown in figure 3. The trays were left to grow up over 7 days, after which diminishing pellicle growth was detected. Upon harvesting, the pellicles were sorted according to granular pellicles (see figure 2 left) and even pellicles (figure 2 right). All pellicles were kept in distilled water in large plastic buckets or containers.

Below shows the general workflow we employed to mass produce our cellulose and illustrates the process of manufacturing biomaterials with significantly different properties despite originating from the same BC source.