Oct 24, 2020
Measuring the amuont of bacteria in a soil sample
- Andreea S1
- 1University of Groningen
- iGEM Groningen 2020
Protocol Citation: Andreea S 2020. Measuring the amuont of bacteria in a soil sample. protocols.io https://dx.doi.org/10.17504/protocols.io.bkrckv2w
License: This is an open access protocol distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited
Protocol status: Other
The protocol is developed based on literature and has not been tested yet.
Created: September 03, 2020
Last Modified: October 24, 2020
Protocol Integer ID: 41476
Keywords: various formulations of bacillus subtili, soil sample colony forming unit, amuont of bacteria, bacillus subtili, microbiology, number of viable bacteria, bacteria, colony forming unit, viable bacteria, cfu, various formulation, unit, present in every formulated product, formulated product, soil, sample
Abstract
Colony Forming Units (c.f.u) is a unit that is used in microbiology to estimate the number of viable bacteria or fungal cells in a sample. It also depends on their ability to multiply under controlled conditions. In the paper published by El-Hassan and Gowen, 2006, they analyzed various formulations of Bacillus subtilis by counting the CFU of B. subtilis present in every formulated product.
Citation
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Troubleshooting
CFU determination
Colony Forming Units (CFU) can be determined by estimating the OD of spore suspension using a tube-reading spectrophotometer adjusted at 1.978 [corresponding to 8.5 · 1010 CFU/ml] at 600nm absorbance wavelength
The formulation will be placed on sterile aluminum foil in pans and air-dried for 24:00:00 with occasional stirring in a laminar airflow cabinet.
Dried formulations (35% moisture content) of B. mycoides will be passed through a 250μm mesh sieve to attain the desired particle size.
Pack in sterilized polypropylene bags, seal and store at room temperature prior to use.
Count CFUs to estimate the number of viable propagules of B. mycoides using the standard dilution platin method described in step 6.
Standard dilution method
Take three 1 g aliquots of the dried powder and place in 99 mL sterile PBST solution (this will include PBS + 0.05 % (v/v) Tween 20). Stir magnetically at high speed for 00:15:00 . Now dilute this suspension with approximately and take 0.2 mL of this suspension and plate on Nutrient Agar (NA) media.
Citations
S. A. El-Hassan and S. R. Gowen. Formulation and Delivery of the Bacterial Antagonist Bacillus subtilis for Management of Lentil Vascular Wilt Caused by Fusarium oxysporum f. sp. lentis
https://doi.org/10.1111/j.1439-0434.2006.01075.x