Gr 11 Fermentor

Micro-bio-tech

Industrial microbiology is now growing microorganisms on a large scale to produce valuable products such as penicillin commercially. This process is referred to as fermentation. Currently, antibiotics are the most important product of fermentation.

The need for penicillin means that there is a demand for large-scale production. Fermenters have been developed that are large-scale vats that can be controlled so that fermentation can take place in an optimal environment. Fermenters have:

• a size that fits the need for optimum production of the desired metabolite, e.g. penicillin

• a means of mechanical agitation or air bubbles for mixing the microorganism with the substrate materials

• devices to maintain the optimum temperature

• probes to monitor the environment for optimum industrial production

• processes for avoiding contamination.

Eventually, the end product can be turned into crystals, packaged, and sold.

BioGas

Biogas is a clean and renewable fuel source produced by the breakdown of organic matter by particular microorganisms

Biogas is primarily composed of methane, carbon dioxide and water vapour
Biogas can be produced from a variety of sources of biomass – including manure, sewage, agricultural waste or food scraps

The production of biogas involves two groups of microorganisms – eubacteria and archaeans (methanogens)

Bacteria first convert the organic material into organic acids and alcohol
Other bacteria convert these products into acetate, carbon dioxide and hydrogen gas
Archaeans then create methane, either via breakdown of acetate or via a reaction between carbon dioxide and hydrogen gas

The production of biogas can occur in small-scale fermenters under anaerobic conditions

The fermenter needs to be maintained at a neutral pH (~ 7) and constant temperature (~ 35ºC) to maximise yield

Small-scale biogas fermenters are air-tight containers that anaerobically break down kitchen and garden wastes to produce biogas

The fermentation process produces a digested slurry (digestate), which can be used as a fertilizer
The biogas forms within the slurry and collects at the top of the chamber, where it can be transported for use via an outlet

The main design elements of a biogas fermenters are an air-tight chamber, an inlet and a vessel for biogas collection

A small-scale fermenter can also be directly linked to toilets for the additional treatment of human excreta
Small-scale biogas fermenters are typically used by households or communities in rural areas as a supplementary fuel source

Biofuels

Fossil fuels are a non-renewable energy source as they take several million years to form through slow geological processes

Fossil fuels include coal (formed from peat) and oil and natural gas (e.g. petroleum)

Biofuels are liquid fuels that are produced from the structural components (biomass) and waste of plant and animal matter

As they are derived from biological processes, they are functionally renewable (provided there is a constant stock of reagents)
Biofuels may use certain industrial wastes as reagents (e.g. CO₂, heat), making them an ecologically sustainable alternative
Biofuels include bioethanol and biodiesel, with efforts ongoing to develop better purification and refinement techniques

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