Microbes are used in food, [blank_start]antibiotics[blank_end], molecular biology, bioremediation, industrial enzymes, genetic [blank_start]engineering[blank_end].
In ancient life microbial fermentation was used to preserve food.
LACTIC ACID FERMENTATION
Bacteria ferment sugars to [blank_start]lactic acid[blank_end]. Accumilates lactic acid which [blank_start]inhibits[blank_end] growth of other organisms by [blank_start]denaturing[blank_end] cell proteins. Bacteria in acidic environments have special membrane [blank_start]pumps[blank_end] to ensure normal function.
Unpasteurised milk undergoes spontaneous lactic acid fermentation.
[blank_start]Lactococcus lactis[blank_end] is important in cheese manufacture.
1) lactic acid [blank_start]fermentation[blank_end]
2) pH drop makes milk [blank_start]precipitate[blank_end] (proteins [blank_start]unfold[blank_end])
3) Proteins and [blank_start]fat[blank_end] form the curd which separates from whey
4) [blank_start]Ripening[blank_end] phase involving secondary microbial transformations. Milk protein is [blank_start]hydrolysed[blank_end] to amino acids, some are further fermented to organic acids and NH3, this is mediated by [blank_start]proteases[blank_end] released from [blank_start]dying[blank_end] lactic acid bacteria.
5) Some soft cheeses are ripened by growth of surface moulds.
Ethanol fermentation is carried out by [blank_start]yeast[blank_end] under [blank_start]anaerobic[blank_end] conditions. There are many [blank_start]different[blank_end] yeasts on grape surfaces, making the process difficult to control. Wine industries often [blank_start]kill[blank_end] wild yeasts and add cultures of [blank_start]S cerevisiae[blank_end]. Low pH ([blank_start]3[blank_end]) combined with high alcohol content makes wines resistant to spoilage.
A secondary fermentation is carried out by members of the [blank_start]lactic acid bacteria[blank_end]. [blank_start]Lactobacillus ones[blank_end] reduces acidity by converting magic acid to lactic acid and CO2. This is [blank_start]malolactic[blank_end] fermentation.
Vitamins- vit [blank_start]B12[blank_end] only synthesised by microorgs. [blank_start]Propionobacterium[blank_end] is used.
Enzymes- Proteases and [blank_start]amylases[blank_end]. (starch digesting)
[blank_start]Citric[blank_end] acid- various bacteria used.
Chemical comps secreted by soil bacteria and moulds to [blank_start]kill[blank_end] other microorgs in the [blank_start]same[blank_end] environment. Chemical warfare weapons used by bacteria and fungi.
Discovery--> Penicillin from [blank_start]Penicillium[blank_end] fungus. This targets [blank_start]murein[blank_end] synthesis.
[blank_start]Streptomycin[blank_end] from soil bacterium called [blank_start]Streptomyces[blank_end]. Targets protein synthesis.
Antibiotics are [blank_start]secondary[blank_end] metabolites mostly produced by eukaryotic fungi or prokaryotic actinomycetes. They are secreted only when the culture enters [blank_start]stationary[blank_end] phase.
Common things targeted by antibiotics are:
[blank_start]trans[blank_end]cription, [blank_start]murein[blank_end] synthesis, protein synthesis, trans[blank_start]lation[blank_end], cell [blank_start]membrane[blank_end].
Natural antibiotics can be [blank_start]chemically[blank_end] modified to give slightly different effects. Penicillin and [blank_start]cephalosporins[blank_end] bind to transpeptidase [blank_start]FtsI[blank_end] in murein synthesis.
We must add cDNA downstream of a promoter so it's highly expressed in E coli
[blank_start]Interferon[blank_end]--->E.coli, antiviral, anti [blank_start]tumour[blank_end]
Insulin--->E.coli, diabetes therapy
Human [blank_start]insulin[blank_end] factor--->E.coli, childhood deficiency of [blank_start]growth[blank_end] hormone
Human [blank_start]Dnase[blank_end] 1---> E.coli, cystic fibrosis therapy
[blank_start]Cleaves[blank_end] DNA, and as there are molecules of DNA in CF mucus, DNase1 cuts this and relieves effects.
Any process using microorganisms to remove [blank_start]toxic[blank_end] dangerous compounds from contaminated soil and [blank_start]groundwater[blank_end]. Cleanup of spills, degradation of pesticides and xenobiotics.
Bacillus [blank_start]thuringiensis[blank_end] (makes spores)
Has a [blank_start]bipyramidal[blank_end] crystal made of [blank_start]insecticidal[blank_end] protein. Once bacteria has been eaten by insect, it enters gut. It is a [blank_start]protoxin[blank_end] and when it is in the gut it gets cleaved and transformed. The toxin binds to [blank_start]epithelial[blank_end] cells on the gut surface. It then [blank_start]oligomerises[blank_end] (molecules join together) on the surface, forming a membrane channel. H2O and ions move in, causing lysis. Leads to death. [blank_start]Plants[blank_end] have been engineered to make this.