Winogradsky column day 22

Winogradsky column
day 22

During the last week the rusty layer has become higher and the contrast to the transparent layer beneath has become more accentuated.

Winogradsky column day 15

Winogradsky column
day 15

After two weeks the water has become turbid. The entire sediment layer is now black, probably as a result of the processes mentioned in the previous blog post. Above the sediment one can see a thin red layer. I guess this is formed by anaerobic purple sulfur bacteria that get energy from H₂S. Further upwards is a break followed by a level with a rusty shade. I suppose this layer is made of non-sulfur purple bacteria, that uses H₂ as energy source. This type of bacteria do not tolerate sulfur as well as the sulfur bacteria, what should explain the gap between the layers, since the concentration of sulfur declines toward the top. At the water surface at the top of the column some lighter particles float.

Rhodopseudomonas palustris, the bacteria I want to isolate is a purple non-sulfur bacteria. Probably it's already possible to do that, even though I'd like to wait one or two more weeks till I try something new.

References

• Winogradsky column: perpetual life in a tube — Edinburgh University

Winogradsky column day 7

Winogradsky column
day 7

The lower part of the sediment has changed color to black. I suppose this is due to the development of metal sulfides from metals and minerals in the mud. Now two types of microorganisms flourish, namely species of the genus Clostridium and so called sulfate-reducing bacteria, e.g. Desulfovibrio. The main reactions of the symbiosis between these microorganisms are shown bellow.

Clostridium

(C6H10O5)n	→	C2H6O	+	–COOH
cellulose (toilet paper)		ethanol		organic acids

Sulfate-reducing bacteria

C2H6O

+

CaSO4

→

H2S

+

CH4

+

CaO

+

CO2

+

H2

ethanol

gypsum

hydrogen sulfide

methane

calcium oxide

carbon dioxide

hydrogen

References

• http://www.personal.psu.edu/faculty/j/e/jel5/biofilms/winogradsky.html
• http://www.biology.ed.ac.uk/archive/jdeacon/microbes/winograd.htm
• http://www.mbio.ncsu.edu/MB452/Winogradsky_columns/wc.html
• http://ecosystems.mbl.edu/SES/MicrobialMethods/MicrobialBiogeochemistry2010.pdf
• Samia Azabou, Tahar Mechichi, Sami Sayadi.Sulfatereduction from phosphogypsum using a mixed culture of sulfate-reducing bacteria. Laboratoire des Bio-procédés, Centre de Biotechnologie de Sfax BP “K”, 3038 Sfax, Tunisia

Starting a Winogradsky column

Winogradsky column
day 1

The concept of composting, to recycle the organic waste for growing new plants, is great. But traditional composting requires that you have a garden or at least some special containers outdoors or in the basement. Is there any other way to draw plant nutrients out of organic waste? Perhaps the method of bokashi would be a good alternative for people living in apartments? This form of composting is based on a mixture of microorganisms called EM (effective microorganism). You can buy dried formulas of EM, but why not make your own? The mixture contains three types of species, of which you can find two in the grocery store: baker yeast (Saccharomyces cerevisiae) and a particular kind of yogurt bacteria (Lactobacillus casei). The challange is to isolate the third organism, Rhodopseudomonas palustris. This bacteria is very common in mud. In order to isolate it I make a Winogradsky column.

Materials and method

In a vessel I blend:

• 30 ml pond mud
• 10 ml shredded toilet paper — as carbon source
• 10 ml gypsum — as sulfur source
• 1 ml chalk — as source of calcium carbonate in case the mud has low calcium amount

View sample origin in a larger map

After stirring all the ingredients together I put the blend on the bottom of a glass bottle. Then I put additional 50 ml mud on top of the previously mentioned blend. At last I fill almost all of the remaining space in the bottle with water from the pond. I cover the bottle with a lid and plastic foil fastened with a rubber band. The column will now stand on a windowsill for a month or two. My goal is to get layers of different species of bacteria in the bottle. Each weekend I'll post a photo showing how the experiment proceeds. After growing the bacteria I plan to isolate Rhodopseudomonas palustris from the column and grow it on a separate medium.

References

• B. Lidesten. Bakterier som använder ljus. Nationellt resurscentrum för biologi och bioteknik. (in Swedish)
• Wikipedia's article about Winogradsky column
• Winogradsky column: perpetual life in a tube — Edinburgh University
• G. Ç. DÖNMEZ, A. ÖZTÜRK, L. ÇAKMAKÇI. Properties of the Rhodopseudomonas palustris Strains Isolated From an Alkaline Lake in Turkey. Tr. J. of Biology. 23 (1999).