Isolation of Streptomyces

Topics: Bacteria, Streptomyces, Antibiotic resistance Pages: 6 (1313 words) Published: November 16, 2010
Research Question
Primary Question- Which Streptomycetes species are antibiotic producers? Secondary Question 1- Which antibiotic or antibiotics does the species produce? Secondary Question 2- Which organisms are the antibiotics effective against? Secondary Question 3- What is the optimum growth media and condition for the antibiotic producing Streptomycetes species?

This is a manipulative lab based experiment. The experiment consists of a primary experiment and a secondary experiment. The aim of the primary stage is to isolate an antibiotic producing Streptomycete from soil sample obtained by myself and investigate the ability of the antibiotic to inhibit other microbes and pathogens.

In the secondary stage of the experiment the optimum condition which promotes antibiotic production will be investigated. Temperature, growth media and possibly other factors will be investigated. Previous studies have shown that 27 degrees was the optimum temperature for Streptomycete to grow, however 37 degrees was the optimum for antibiotic production. [2]

It is not certain which Streptomycete will be isolated from the soil sample. But almost certainly it will produce one or more antibiotic. Based on previous researches Streptomycete isolated from Mount Everest, the antibiotic produced was effected against all of the gram negative test organism except the Proteus spp. gram positive bacteria were less sensitive and Pseudomonas aeruginosa was resistant. [2] In our experiment we expect something similar.

➢ To isolate one or more Streptomyces spp. which produces antibiotics. ➢ To find out what antibiotics it is and investigate what micro-organisms its effective against. ➢ To investigate what the optimum growth condition is for the antibiotic producing Streptomyces species (E.g. growth media, temperature…etc.).

➢ Isolation- isolating the antibiotic-producing Streptomyces species from different soil samples. ➢ Determine the effectiveness of the antibiotic on several other micro-organisms. Which microbes is it effective against? Which microbes are resistant to it? E.g. E.coli species, Salmonella species…etc. ➢ Testing the optimum growth temperature of antibiotic production by the Streptomycetes. Does it grow best at 20 degrees c, 30 degrees c…. etc. ➢ Testing the optimum temperature of antibiotic production by the Streptomycetes isolated. Does it produce most at 20 degrees c, 30 degrees c… etc. ➢ Once the above range had been determined, we can also narrow the scale to 5 upwards, e.g. 10-20 would be 15, 20-30 would be 25.

Streptomyces spp. are gram-positive bacteria found in soil water and colonizing plants. They are the largest genus of Actinomycete bacteria. The Actinomycetes produce roughly 40% of all antibiotics. Streptomyces spp. produce over 80% of actinomycete-derived antibiotics.[1] Some examples of antibiotics and their producers are listed below. • Erythromycin (S. erythraeus)

• Neomycin (from S. fradiae)
• Streptomycin (from S. griseus)
• Tetracycline (from S. rimosus)
• Vancomycin (from S. orientalis)
• Daptomycin (from S. roseosporus)
• Rifamycin (from S. mediterranei)
• Chloramphenicol (from S. venezuelae)
• Puromycin (from S. alboniger)
• Lincomycin (from S. lincolnensis)
There is one species in particular Streptomyce coelicolor which produces four antibiotics; prodiginine, actinorhodin, methylenomycin and calcium-dependent antibiotic. [1] These soil actinomycetes are preferentially screened for antibiotic production which has immense biotechnological value. [2]

Experimental Methods
Primary Stage
Soil sample would be mixed with water to release any microbes. The water containing microbes would be streak plated onto a known nutrient source which is preferred by Streptomycetes. An antibiotic, which Streptomycetes are resistant to, may also be prepared onto the nutrient source, to help in the illumination...
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