Lab Results Fermenter

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I. OBJECTIVES:

To determine the amount of anti-microbial peptide production by Staphylococcus warneri under various conditions when 2L and 10L Fermented.

To Test the effects of one uncontrolled parameters sush as pH, Temperature or dissolved Oxygen and compare findings.

To produce anti-microbial activity from Staphylococcus warneri.

II. INTRODUCTION:

Staphylococcus warneri is a member of bacterial genus Staphylococcus, consisting of Gram-positive bacteria with spherical cells appearing in clusters. Colonies of S. warneri are usually tan, yellow and about 2-4mm in diameter after 48 hours incubation at 35°C. It is commonly found as part of the skin flora on humans and animals. S. warneri rarely causes disease, but may occasionally cause infection in patients whose immune system is compromised. S. warneri is known to produce antimicrobial peptide activity in the form of Nisin. The optimum conditions for this to occur are pH 7.

Nisin is a polycylic antibacterial peptide with 34 amino acid residues used as a food preservative.It is produced by bacterium and which contains antimicrobial activity and which is known as a bacteriocin. Nisin has been found to have properties that can control spoilage caused by lactic acid bacteria. It is used in processed cheese, meats, beverages, etc. during production to extend shelf life by suppresing Gram-positive spoilage and pathogenic bacteria. In food it is common to use Nisin at levels depending on the food type regulatory approval. Nisin cannot be produced chemically therefore it has to be synthesised using fermentation.

During fermentation various stages of growth occur and as a result different conditions can occur during this fermentation process, eg pH, most organisms produce acid as they grow and therefore in the Lag phase ( a period of adptation for the cells to their new environment, new enzymes are synthesized) and in the lag phase can produce alkaline substances and therefore pH plays an important role in efficient fermentation. As acid is produced alkaline substance needs to be added to the process to maintain the optimum pH of 7 and likewise in the lag phase when alkaline substances are produced, acidic substance needs to be added to maintain the pH, temperature, and oxygen.

III. MATERIALS AND METHODS:“As per manual.”
IV. RESULTS:

TABLE 1.1 History Plot Vessel 1 - 2L NO Temperature control:

TABLE 1.2 History Plot Vessel 2 – 2L NO Air Flow:

TABLE 1.3 History Plot Vessel 3 – 2L NO pH control:

TABLE 1.4 History Plot Vessel 4 – 2L Optimum conditions:

TABLE 1.5 History Plot Vessel 5 – 10L Optimum conditions:

TABLE 1.6 Fermentation conditions for each Vessels 1 - 5:

Parameter
Vessel Number

Vessel 1
Vessel 2
Vessel 3
Vessel 4
Vessel 5 (10L)
pH
7
7
No control
7
7
Agitation Speed (RPM)
150
150
150
150
150
Temp oC
No Control
37
37
37
37
Airflow (L/min)
2
No air flow
2
2
2

TABLE 1.7 Results for antimicrobial peptide activity in 2 L or 10 L fermenters:

Time (post inoculation)
Vessel 1
Vessel 2
Vessel 3
Vessel 4
Vessel 5
13:00
(4.5 hours)
No activity
No activity
Neat
Neat
Neat; 1:2
14:00
(5.5 hours)
No activity
Neat; 1:2
Neat; 1:2
Neat; 1:2
No results
15:00
(6.5 hours)
No activity
Neat; 1:2
Neat
Neat; 1:2
Neat; 1:2; 1:4;1:8
16:00
(7.5 hours)
No activity
Neat
Neat;1:2;1:4
Neat; 1:2
Neat; 1:2; 1:4;1:8
9:00
(24.5 hours)
No activity
Neat
Neat;1:2;1:4
Neat;1:2;1:4;1:8
Neat; 1:2; 1:4;1:8

V. DISCUSSION:

In this practical, Fermentation is used to scale testing in laboratory. The fermenters in the Laboratory are based on a batch system, with feeds to control the pH and Oxygen levels and Temperature. All parameters are controlled using sensor probes in the vessels connected to a data logging software system. The vessels 4 and 5...
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