Biotechnology

Technology based on biology. Involves the exploitation of living organisms or

biological processes to improve agriculture, animal husbandry, food

science, medicine and industry

Why are microbes particularly suitable for use in biotechnology?

Lag phase: organisms are adjusting to the surrounding conditions. The cells are active but not reproducing The length of this period depends on growing conditions.

Log (exponential) phase: the population size doubles each generation as every individual has the space and nutrients to reproduce. In length of this depends on how quickly the organisms reproduce and take up the available nutrients and space.

Stationary phase: nutrient levels decrease and waste products build up. Individual organisms die at the same rate as new organisms are produced (in an open system this would be the carrying capacity)

Decline or death phase: nutrient exhaustion and increased levels of toxic waste products and metabolites lead to the death rate increasing above the rate of reproducing. Eventually all organisms will die in a closed system.

Growth of microbes in a closed culture

Metabolite – substances produced in metabolismTwo sorts1. Primary metabolite – substance produced by

a microbe as part of it’s normal growth. Product of essential processes

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Primary metabolite production

Metabolite – substances produced in metabolism

2. Secondary metabolite – products of non essential processes, processes that are not part of normal growth

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Secondary metabolite production

How can growth conditions be manipulated to maximise yield of product?

•Temperature

•Nutrients

•Oxygen availability

•pH

What is the difference between batch and continuous culture?

•A continuous culture- nutrients are added and products removed from the tank at regular intervals, or continuously

•What sort of metabolite would this be used to produce?

What is the difference between batch and continuous culture?

•A batch culture - micro organisms are mixed with a fixed quantity of nutrient solution and allowed to grow for a fixed period of time, with nothing added or removed (except oxygen and carbon dioxide)

•At the end of the time period the products are removed and the fermentation tank is emptied.

•What sort of metabolite would this be used to produce?

•Asepsis- The absence of unwanted micro

organisms

•Aseptic technique– Refers to any measure taken at any point in a biotechnological process to ensure that unwanted micro organisms do not contaminate the culture that is being grown or the products being extracted

How else can equipment be sterilised?

Chemicals (bleach, ethanol etc.)BoilOvenAutoclave – 121˚C for 15 minutesSteamIrradiation