Coding
Pil
Part:BBa_K1692034
Designed by: Thai Nguyen Group: iGEM15_Stanford-Brown (2015-09-18)
Pank + Imperial + Lysis
Using cell lysis to facilitate P(3HB) extraction from E. coli
Since bacteria that naturally synthesize P(3HB) use the plastic as an energy storage mechanism, the plastic is produced inside the cell and stays there. Currently, the isolation of P(3HB) from the cells and culture media is one of the main bottlenecks in the P(3HB) production process – and the main source of its high cost of approximately $4-6 USD [6]. Traditional isolation methods include the use of large amounts of chemicals that can be hazardous to human health and the environment, such as chloroform and sodium hypochlorite, or other problems such as large volumes of waste water produced or impurities in the polymers [6]. Since one of our team’s goals has been to reduce up-mass of materials on space flights, we wanted to minimize the amounts of harmful (and heavy) chemicals that would need to be brought up as payload to extract the P(3HB).
We sought to accomplish this by introducing a lysis device into the PSB1C3 plasmid that contained the phaCAB operon and the gene for pantothenate kinase. The lysis device was developed by the 2008 Berkeley iGEM team. The device contains T7 phage antiholin under a weak promoter, and T7 phage holin and endolysin inducible under (L)-arabinose. This lysis device was not reported to kill entire populations of E. coli, and we saw this as an advantage for a continuous plastic-production system. We would be able to cause part of the population to lyse and release its P(3HB) into the media, and the rest of the cells can continue to grow. The rest of the population would continue growing and producing plastic. The plastic can be recovered from the media by causing the granules to aggregate, and then requiring lower amounts of solvents and less time to complete the purification process [7]. We were able to obtain preliminary data showing that the lysis system works.
Preliminary lysis experiments After inducing cell lysis with (L) arabinose, we wanted to check whether there were viable cells remaining. These experiments were done at the end of the summer; if we had more time, we could have used another method of testing cell lysis, such as a beta galactosidase assay. To check quickly, we streaked the same volume of cells onto two halves of a plate to see which grew more. The two left halves show growth of 5uL of culture after lysis. The two right halves show our negative controls. The top one is cells from a culture that contained our plastic genes, but no lysis system; the bottom one is cells from a culture that contained the lysis system and the plastic genes but were not induced. We see more growth in the right two halves, which is promising although not conclusive.
Sequence and Features
Assembly Compatibility:
- 10COMPATIBLE WITH RFC[10]
- 12COMPATIBLE WITH RFC[12]
- 21COMPATIBLE WITH RFC[21]
- 23COMPATIBLE WITH RFC[23]
- 25COMPATIBLE WITH RFC[25]
- 1000COMPATIBLE WITH RFC[1000]
Preliminary lysis experiments After inducing cell lysis with (L) arabinose, we wanted to check whether there were viable cells remaining. These experiments were done at the end of the summer; if we had more time, we could have used another method of testing cell lysis, such as a beta galactosidase assay. To check quickly, we streaked the same volume of cells onto two halves of a plate to see which grew more. The two left halves show growth of 5uL of culture after lysis. The two right halves show our negative controls. The top one is cells from a culture that contained our plastic genes, but no lysis system; the bottom one is cells from a culture that contained the lysis system and the plastic genes but were not induced. We see more growth in the right two halves, which is promising although not conclusive.
Sequence and Features
Assembly Compatibility:
- 10COMPATIBLE WITH RFC[10]
- 12COMPATIBLE WITH RFC[12]
- 21COMPATIBLE WITH RFC[21]
- 23COMPATIBLE WITH RFC[23]
- 25COMPATIBLE WITH RFC[25]
- 1000COMPATIBLE WITH RFC[1000]
[edit]
Categories
Parameters
| None |