Industrial Microbiology

their small cells contain a relatively high amount of DNA and RNA which contains purines which are hard for humans to metabolize

they ferment sugar to lactic acid, increasing the acidity and denaturing proteins that coagulate

• yeast, lactic acid bacteria and acetic acid bacteria invovled
• must happen immediately
• use indigenous molecules
• can not be stored or exported

• cells
• product from bioconversion of substrate and cells
• products from cells

use of microorganisms, usually grown on a large scale, to produce valuable commercial products or carry out important chemical transformations

• enhancement of exisiting microbial processes/reactions
• production of new microbial products via gene manipulation (microbial biotechnology)

reactions carried out by microorganisms in industrial microbiology

• yield:
• produce substance of interest
• capable of growth and product formation in large-scale culture
• substance of interest is easily obtained from culture
• amendable to genetic manipulation and genetically stable
• easy to inoculate into large fermentors

• safety:
• not pathogenic

• cost:
• grow rapidly and produce product in short time period
• grow in relatively inexpensive liquid culture medium (byproduct from another process)
• can sell off byproduct from process
• cost of purification

bottom line: cost

• formed during growth phase
• production is coupled with growth
• ex. alcohol

• formed near end of growth phase/stationary phase
• not essential for growth and reproduction
• production is highly dependent on growth conditions
• often produced as group of closely-related structures
• can often achieve dramatic overproduction of secondary metabolites
• ex. penicillin

• growth phase
• primary vs. secondary metabolism
• limitations on product formation
• regulation of gene expression, protein expression, protein activity important
• introducing novel genes
• understand regulation

• substrate availability
• global repression
• feedback inhibition
• product stability
• conversion of product to other compounds

• codon usage
• copy number
• mini operon - expression is co-regulated
• stabilize and destabilize transcript

• allosteric effectors
• catabolite repression
• rate limiting step vs. shared control

• vessel used for aerobic or anaerobic processes
• scale up is critical and complicated

• can facilitate enzymatic reaction in large scale continuous systems
• stabilize enzymes - limit denaturation
• immobilization via: bonding, cross-linking, enzyme inclusion