https://en.wikipedia.org/wiki/Pfizer%E2 ... ufacturingPfizer and BioNTech are manufacturing the vaccine in their own facilities in the United States and in Europe. The license to distribute and manufacture in China was purchased by Fosun, alongside its investment in BioNTech.[24][88]
Pfizer indicated in its 9 November press release that 50 million doses could be available by the end of 2020, with about 1.3 billion doses provided globally by 2021.[28]
Manufacturing the vaccine requires a three-stage process. The first stage involves the molecular cloning of DNA plasmids that code for the spike protein by infusing them into Escherichia coli bacteria. For all markets, this stage is conducted in the United States,[89] at a small Pfizer pilot plant in Chesterfield, Missouri[90][91] (near St. Louis). After four days of growth, the bacteria are killed and broken open, and the contents of their cells are purified over a week and a half to recover the desired DNA product. The DNA is bottled and frozen for shipment. Safely and quickly transporting the DNA at this stage is so important that Pfizer has used its company jet and helicopter to assist.[92]
The second stage is being conducted at a Pfizer plant in Andover, Massachusetts,[93] in the United States, and at BioNTech's plants in Germany.[89] The DNA is used as a template to build the desired mRNA strands,[92] which takes about four days.[89] Once the mRNA has been created and purified, it is frozen in plastic bags about the size of a large shopping bag, of which each can hold up to 10 million doses. The bags are placed on trucks which take them to the next plant.[92]
The third stage is being conducted at Pfizer plants in Portage, Michigan[94] (near Kalamazoo) in the United States, and Puurs in Belgium. This stage involves combining the mRNA with lipid nanoparticles, then filling vials, boxing vials, and freezing them.[92] Croda International subsidiary Avanti Polar Lipids is providing the requisite lipids.[95] As of November 2020, the major bottleneck in the manufacturing process is combining mRNA with lipid nanoparticles.[92] At this stage, it takes only four days to go from mRNA and lipids to finished vials, but each lot must then spend several weeks in deep-freeze storage while undergoing verification against 40 quality-control measures.[89]
From the template link (no real detail on what the source of the polymerase is...there are plants to make these
Initiation
Transcription begins with the binding of RNA polymerase, together with one or more general transcription factors, to a specific DNA sequence referred to as a "promoter" to form an RNA polymerase-promoter "closed complex". In the "closed complex" the promoter DNA is still fully double-stranded.[7]
RNA polymerase, assisted by one or more general transcription factors, then unwinds approximately 14 base pairs of DNA to form an RNA polymerase-promoter "open complex". In the "open complex" the promoter DNA is partly unwound and single-stranded. The exposed, single-stranded DNA is referred to as the "transcription bubble."[7]
RNA polymerase, assisted by one or more general transcription factors, then selects a transcription start site in the transcription bubble, binds to an initiating NTP and an extending NTP (or a short RNA primer and an extending NTP) complementary to the transcription start site sequence, and catalyzes bond formation to yield an initial RNA product.[7]
Elongation
Simple diagram of transcription elongation
One strand of the DNA, the template strand (or noncoding strand), is used as a template for RNA synthesis. As transcription proceeds, RNA polymerase traverses the template strand and uses base pairing complementarity with the DNA template to create an RNA copy (which elongates during the traversal). Although RNA polymerase traverses the template strand from 3' → 5', the coding (non-template) strand and newly formed RNA can also be used as reference points, so transcription can be described as occurring 5' → 3'. This produces an RNA molecule from 5' → 3', an exact copy of the coding strand (except that thymines are replaced with uracils, and the nucleotides are composed of a ribose (5-carbon) sugar where DNA has deoxyribose (one fewer oxygen atom) in its sugar-phosphate backbone).[citation needed]
mRNA transcription can involve multiple RNA polymerases on a single DNA template and multiple rounds of transcription (amplification of particular mRNA), so many mRNA molecules can be rapidly produced from a single copy of a gene.[citation needed] The characteristic elongation rates in prokaryotes and eukaryotes are about 10-100 nts/sec.[42] In eukaryotes, however, nucleosomes act as major barriers to transcribing polymerases during transcription elongation.[43][44] In these organisms, the pausing induced by nucleosomes can be regulated by transcription elongation factors such as TFIIS.[44]